CompTIA A+ Exam > CompTIA A+ Notes > Core 2 > Cheatsheet: Software Troubleshooting
Cheatsheet: Software Troubleshooting
1. Windows Troubleshooting
1.1 Common Windows Symptoms
| Symptom | Common Causes & Solutions |
|---|---|
| Blue Screen of Death (BSOD) | Hardware failure, driver issues, RAM problems; check error code, update drivers, run memory diagnostic, check Event Viewer |
| Slow Performance | Insufficient RAM, malware, too many startup programs, fragmented HDD; disable startup items, run malware scan, add RAM, defragment drive |
| Boot Failure | Corrupt boot files, missing BOOTMGR, disk errors; use bootrec /fixmbr, /fixboot, /rebuildbcd commands from Recovery Environment |
| Frequent Crashes | Overheating, bad drivers, malware, failing hardware; check temperatures, update drivers, scan for malware, test RAM/HDD |
| Application Crashes | Incompatible software, corrupt installation, insufficient resources; reinstall application, check compatibility mode, update software |
| Low Memory Warnings | Too many programs running, memory leak, insufficient RAM; close unnecessary programs, restart system, add RAM |
| USB Controller Resource Warnings | Too many USB devices, power issues; use powered USB hub, reduce connected devices, update USB drivers |
| System Instability | Corrupt system files, bad updates, malware; run sfc /scannow, DISM, uninstall recent updates, malware scan |
| No OS Found | Boot order incorrect, failed HDD, corrupt boot sector; check BIOS boot order, test HDD health, repair boot files |
| Sluggish Response | High disk usage, background processes, insufficient resources; check Task Manager, disable unnecessary services, upgrade hardware |
| Boots to Safe Mode | Startup setting changed, corrupt drivers, system protection; use msconfig to change boot options, fix driver issues |
1.2 Windows Recovery Tools
| Tool | Purpose & Usage |
|---|---|
| System Restore | Reverts system to previous restore point; preserves personal files, removes recent software/driver changes |
| Startup Repair | Fixes boot problems automatically; accessed from Recovery Environment, repairs boot configuration |
| System File Checker (sfc /scannow) | Scans and repairs corrupt system files; run from elevated command prompt, requires Windows installation media for repairs |
| DISM (Deployment Image Servicing) | Repairs Windows component store; use DISM /Online /Cleanup-Image /RestoreHealth before sfc /scannow |
| chkdsk | Checks and repairs disk errors; use chkdsk /f (fixes errors), /r (locates bad sectors), requires reboot for system drive |
| bootrec | Repairs boot configuration; /fixmbr (repairs MBR), /fixboot (writes boot sector), /rebuildbcd (rebuilds BCD) |
| System Image Recovery | Restores full system backup; requires previously created system image, replaces entire system |
| Reset This PC | Reinstalls Windows; Keep My Files (preserves data) or Remove Everything (clean install) |
1.3 Windows Utilities
| Utility | Function |
|---|---|
| msconfig | System Configuration; manage startup programs, boot options, services, diagnostic startup |
| Task Manager | Monitor performance, end tasks, manage startup programs, view processes and services |
| Event Viewer | View system logs; Application, Security, System logs; filter by error level, find event IDs |
| Performance Monitor | Track system performance metrics; CPU, memory, disk, network counters |
| Resource Monitor | Real-time detailed resource usage; CPU, memory, disk, network activity per process |
| Device Manager | Manage hardware devices; update/rollback drivers, disable devices, view conflicts (yellow exclamation) |
| Disk Management | Manage partitions, format drives, assign drive letters, extend/shrink volumes |
| Services | Manage Windows services; start/stop services, set startup type (Automatic, Manual, Disabled) |
| Registry Editor (regedit) | Edit Windows registry; backup before changes, HKLM and HKCU are main hives |
2. Malware Symptoms and Removal
2.1 Malware Types
| Malware Type | Characteristics |
|---|---|
| Virus | Attaches to files, replicates when host executes, requires user action to spread |
| Worm | Self-replicating, spreads without user intervention, exploits network vulnerabilities |
| Trojan | Disguised as legitimate software, does not self-replicate, provides backdoor access |
| Ransomware | Encrypts files, demands payment for decryption key, spreads via email/exploit kits |
| Spyware | Monitors user activity, collects information without consent, tracks browsing/keystrokes |
| Rootkit | Hides malware presence, operates at kernel level, difficult to detect and remove |
| Adware | Displays unwanted advertisements, tracks browsing, may redirect searches |
| Keylogger | Records keystrokes, captures passwords and sensitive data, hardware or software-based |
| Botnet | Network of infected computers, controlled remotely, used for DDoS attacks or spam |
| Cryptominer | Uses system resources to mine cryptocurrency, causes high CPU usage and slow performance |
2.2 Malware Symptoms
- Pop-ups appearing frequently, especially when browser is closed
- Browser redirects to unwanted websites or search engines
- Slow system performance and high CPU/memory usage without cause
- New toolbars or browser extensions installed without permission
- Antivirus disabled or unable to update
- Files renamed, encrypted, or inaccessible
- Unusual network activity or high bandwidth usage
- Fake antivirus alerts or security warnings
- Email spam being sent from user's account
- Desktop icons changed or new programs installed
- System crashes or freezes more frequently
- Disabled security tools or Task Manager
2.3 Malware Removal Process
2.3.1 Identification
- Identify symptoms and behavior
- Note recent changes or installations
- Check Task Manager for suspicious processes
- Review startup programs
2.3.2 Quarantine
- Disconnect from network immediately
- Disable System Restore to prevent reinfection
- Boot into Safe Mode or Safe Mode with Networking
- Prevent malware from running at startup
2.3.3 Disable System Restore
- Right-click This PC > Properties > System Protection
- Select drive and click Configure
- Select "Disable system protection"
- Re-enable after cleaning and verification
2.3.4 Remediation
- Update antivirus definitions before scanning
- Run full system scan with antivirus software
- Use anti-malware tools (Malwarebytes, AdwCleaner)
- Remove detected threats and quarantine suspicious files
- Manually delete remaining files and registry entries
- Reset browser settings to defaults
2.3.5 Schedule Scans
- Configure automatic daily or weekly scans
- Schedule during off-hours to minimize disruption
- Enable real-time protection
- Keep definitions updated automatically
2.3.6 Educate End User
- Avoid suspicious email attachments and links
- Download software only from trusted sources
- Keep operating system and software updated
- Use strong passwords and enable multi-factor authentication
- Recognize phishing attempts and social engineering
2.4 Best Practices for Prevention
- Install and maintain updated antivirus software
- Enable firewall on all systems
- Keep operating system and applications patched
- Use standard user accounts instead of administrator
- Implement application whitelisting
- Disable autorun/autoplay for removable media
- Regular backups stored offline
- User education and security awareness training
3. Mobile Device Issues
3.1 Common Mobile Symptoms
| Symptom | Troubleshooting Steps |
|---|---|
| Slow Performance | Close background apps, clear cache, uninstall unused apps, restart device, check storage space, update OS |
| Battery Drain | Check battery usage stats, disable location services when not needed, reduce screen brightness, close background apps, disable push notifications |
| Overheating | Remove case, close intensive apps, avoid charging while using, check for malware, update apps and OS |
| Cannot Broadcast to External Monitor | Verify adapter compatibility, check cable connections, enable screen mirroring in settings, restart both devices |
| No Sound from Speakers | Check volume level, disable Bluetooth (may be connected to external device), restart device, check headphone jack for debris |
| GPS Not Functioning | Enable location services, check app permissions, ensure GPS is enabled in settings, restart device, update maps data |
| Touchscreen Non-responsive | Clean screen, remove screen protector, restart device, boot to safe mode, factory reset if persistent |
| Apps Not Loading | Force stop app, clear app cache and data, check for updates, reinstall app, verify storage space |
| App Crashes | Update app, clear cache, reinstall app, check OS compatibility, verify sufficient RAM |
| Unable to Decrypt Email | Verify certificates installed, check S/MIME settings, ensure private key present, verify sender's public key |
| Short Battery Life | Calibrate battery, enable battery saver mode, reduce sync frequency, disable vibration, replace aging battery |
| Connectivity Issues | Toggle airplane mode, forget and reconnect to network, reset network settings, update carrier settings |
3.2 Mobile OS Issues
| Issue | Resolution |
|---|---|
| Device Won't Boot | Force restart, charge for 30 minutes, boot to recovery mode, factory reset, flash firmware |
| Frozen Screen | Force restart (hold power + volume down for 10 seconds), remove battery if removable, boot to safe mode |
| Random Reboots | Update OS, uninstall recently added apps, check for overheating, factory reset, hardware fault |
| Storage Full | Delete unused apps, clear cache, move photos/videos to cloud, use SD card, delete large files |
| OS Update Failed | Ensure sufficient storage, connect to stable Wi-Fi, charge to 50%+, clear cache partition, manual update via computer |
3.3 Mobile Security Issues
- High data usage: Check for malicious apps, review background data usage, restrict background data
- High number of ads: Scan for adware, uninstall suspicious apps, use ad blocker, factory reset if needed
- Leaked personal files: Change passwords, enable remote wipe, check app permissions, scan for spyware
- Data transmission over limit: Review app data usage, disable auto-updates over cellular, use Wi-Fi monitoring apps
- Unauthorized account access: Change passwords immediately, enable two-factor authentication, review account activity
- Unauthorized root access: Unroot device, factory reset, verify bootloader status, reinstall official OS
4. Application Issues
4.1 Common Application Problems
| Problem | Solution |
|---|---|
| Application Will Not Install | Check system requirements, verify sufficient disk space, run as administrator, disable antivirus temporarily, use compatibility mode |
| Application Crashes on Startup | Update application, reinstall, check Event Viewer for errors, run in compatibility mode, verify .NET Framework installed |
| Application Fails to Uninstall | Use Programs and Features, run uninstaller as admin, use vendor removal tool, edit registry to remove entries, use third-party uninstaller |
| Missing DLL Files | Reinstall application, download DLL from legitimate source, run sfc /scannow, install Visual C++ Redistributables |
| Compatibility Issues | Right-click > Properties > Compatibility tab, select previous Windows version, run as administrator, disable display scaling |
| Cannot Open File Type | Set default program (Settings > Apps > Default apps), install required application, repair file association in registry |
4.2 Windows Update Issues
| Issue | Resolution |
|---|---|
| Updates Fail to Install | Run Windows Update Troubleshooter, clear SoftwareDistribution folder, run DISM and sfc, manually download update |
| Updates Cause System Issues | Uninstall recent updates (Settings > Update & Security > View update history), use System Restore, defer feature updates |
| Windows Update Service Not Running | Services.msc > Windows Update > set to Automatic, restart service, check dependencies (BITS, Cryptographic Services) |
| Stuck Downloading or Installing | Restart Windows Update service, delete SoftwareDistribution folder contents, run update troubleshooter, reset Windows Update components |
4.3 Browser Issues
| Issue | Solution |
|---|---|
| Browser Crashes | Clear cache and cookies, disable extensions, reset browser settings, reinstall browser, scan for malware |
| Slow Loading Pages | Clear browsing data, disable unnecessary extensions, check DNS settings, flush DNS cache (ipconfig /flushdns) |
| Pop-ups and Redirects | Enable pop-up blocker, scan for adware/malware, remove suspicious extensions, reset browser to defaults |
| Certificate Errors | Check system date/time, clear SSL cache, update browser, disable antivirus SSL scanning, import root certificates |
| Cannot Connect to Websites | Check internet connection, flush DNS, reset TCP/IP stack, disable proxy settings, check firewall rules |
4.4 Email Client Issues
- Cannot send/receive: Verify server settings (SMTP, IMAP, POP3), check credentials, verify firewall not blocking ports, test account online
- Authentication errors: Re-enter password, enable "less secure apps" if required, use app-specific password, check two-factor authentication
- Emails stuck in outbox: Check attachment size limits, verify internet connection, resend individual messages, clear outbox and retry
- Missing emails: Check spam/junk folder, verify filters and rules, check storage quota, restore from deleted items
5. Security Issues
5.1 Security Symptoms
| Symptom | Indication & Action |
|---|---|
| Pop-up Windows | Adware or browser hijacker; scan for malware, reset browser settings, remove unwanted extensions |
| Browser Redirection | Hijacked DNS or hosts file; check DNS settings, scan hosts file (C:\Windows\System32\drivers\etc), reset browser |
| Security Alerts | Verify legitimacy (may be fake); check from trusted security software only, investigate in Event Viewer |
| False Alerts | Rogue antivirus software; do not click, boot to safe mode, remove fake AV, run legitimate malware scan |
| Altered System Files | Malware infection or corruption; run sfc /scannow, check file signatures, restore from backup |
| Missing/Renamed Files | Ransomware or malware; isolate system, identify infection, restore from backup, do not pay ransom |
| Unwanted Notifications | Adware or PUP; review notification settings, uninstall suspicious programs, scan for malware |
| OS Update Failures | Malware preventing updates; scan system, run update troubleshooter, manually install updates |
5.2 Access Control Issues
| Issue | Resolution |
|---|---|
| Access Denied Errors | Check NTFS permissions, take ownership of file/folder, run as administrator, verify user group membership |
| Cannot Delete File | Close programs using file, boot to safe mode, use command prompt (del command), check file permissions |
| Shared Folder Not Accessible | Verify network connectivity, check share permissions, ensure file sharing enabled, verify credentials |
| Invalid Certificate Warnings | Check system date/time, verify certificate validity period, install root CA certificate, renew expired certificate |
5.3 User Account Issues
- Cannot log in: Verify credentials, check Caps Lock, reset password, use safe mode, check account status (disabled/locked)
- Account locked out: Wait for lockout duration, have admin unlock, check Group Policy lockout settings
- Profile corruption: Create new user profile, copy data from old profile (C:\Users\username), delete corrupt profile
- Temp profile loaded: Restart computer, check registry (ProfileList), restore profile from backup, create new profile
5.4 Network Security
- Unauthorized network access: Change Wi-Fi password, enable WPA3/WPA2, disable WPS, enable MAC filtering, update router firmware
- Man-in-the-middle attacks: Use VPN on public networks, verify HTTPS, check certificate validity, avoid unsecured Wi-Fi
- DNS hijacking: Flush DNS cache, use trusted DNS servers (8.8.8.8, 1.1.1.1), check router DNS settings, scan for malware
6. Printing Issues
6.1 Common Printer Problems
| Problem | Troubleshooting |
|---|---|
| Printer Not Found | Check physical connections, verify printer powered on, restart print spooler service, reinstall printer driver |
| Print Jobs Stuck in Queue | Clear print queue, restart print spooler (services.msc > Print Spooler), delete files in C:\Windows\System32\spool\PRINTERS |
| Garbled or Incorrect Output | Update printer driver, check document formatting, verify correct printer language (PCL/PostScript), reinstall driver |
| Access Denied to Printer | Check printer permissions, verify user in correct group, ensure printer shared properly, run as administrator |
| Slow Printing | Reduce print quality, update driver, check network connection, add printer memory, simplify graphics |
| Driver Unavailable | Download driver from manufacturer, use Windows Update for drivers, install compatible driver for OS version |
6.2 Network Printer Issues
- Cannot find network printer: Verify IP address, check network connectivity, ensure printer sharing enabled, disable firewall temporarily to test
- Intermittent connection: Check network cable, verify static IP or DHCP reservation, update printer firmware, restart print server
- Authentication errors: Verify credentials, check share permissions, ensure user account has print permission
6.3 Print Spooler Issues
- Spooler keeps stopping: Clear spooler folder, remove corrupt print jobs, check for malware, rebuild spooler database
- Restart Print Spooler: Services.msc > Print Spooler > Restart, or use command: net stop spooler && net start spooler
- Disable and re-enable: Stop service, delete contents of spool folder, restart service
7. Network Connectivity Issues
7.1 Common Network Problems
| Problem | Troubleshooting |
|---|---|
| No Internet Connection | Check physical connections, restart modem/router, verify IP configuration (ipconfig), renew IP (ipconfig /renew), check DNS |
| Limited Connectivity | Indicates DHCP failure or invalid IP; release/renew IP, check DHCP server, assign static IP, restart network adapter |
| Intermittent Connection | Check cable quality, update network drivers, scan for interference, verify router firmware, check for IP conflicts |
| Cannot Connect to Network Share | Verify credentials, check network path, ensure File and Printer Sharing enabled, ping server by IP and name |
| Slow Network Speed | Check bandwidth usage, scan for malware, update network drivers, check for interference, test with wired connection |
| DNS Resolution Failure | Flush DNS (ipconfig /flushdns), change DNS servers, check hosts file, restart DNS client service |
| IP Address Conflict | Release and renew IP, use static IP outside DHCP range, restart router, identify conflicting device |
7.2 Network Commands
| Command | Purpose |
|---|---|
| ipconfig | Display IP configuration; /all (detailed), /release (release IP), /renew (obtain new IP), /flushdns (clear DNS cache) |
| ping | Test connectivity to host; ping 8.8.8.8 (test internet), ping hostname (test DNS), -t (continuous ping) |
| tracert | Trace route to destination; shows each hop, identifies where connection fails |
| nslookup | Query DNS records; test DNS resolution, verify A records, check mail servers |
| netstat | Display network connections; -a (all connections), -n (numeric), -b (executable), -o (process ID) |
| net use | Map network drives; net use Z: \\server\share, disconnect with /delete |
| netsh | Network shell utility; reset TCP/IP (netsh int ip reset), reset Winsock (netsh winsock reset) |
| pathping | Combines ping and tracert; shows packet loss per hop, identifies problematic routers |
7.3 Wi-Fi Issues
- Cannot see wireless network: Enable wireless adapter, check router broadcasting SSID, verify correct frequency (2.4GHz/5GHz)
- Weak signal: Move closer to router, reduce interference, update adapter drivers, change Wi-Fi channel
- Authentication errors: Verify password, check security type (WPA2/WPA3), forget network and reconnect, update adapter drivers
- Connected but no internet: Restart router, check WAN connection, verify DNS settings, release/renew IP
7.4 VPN Issues
- Cannot connect to VPN: Verify credentials, check firewall rules, ensure VPN service running, verify server address
- VPN connects but no access: Check routing table, verify split tunneling settings, confirm DNS configuration
- Frequent disconnections: Check network stability, update VPN client, adjust timeout settings, try different protocol
8. Performance Issues
8.1 System Performance Problems
| Problem | Diagnosis & Solution |
|---|---|
| High CPU Usage | Check Task Manager for process, end unnecessary tasks, scan for malware, update drivers, add cooling |
| High Memory Usage | Identify memory-heavy processes, close unused programs, add RAM, check for memory leaks, disable startup programs |
| High Disk Usage | Check for Windows Search indexing, disable Superfetch/Prefetch, run disk cleanup, check for failing drive, scan for malware |
| Disk Thrashing | Indicates insufficient RAM; add memory, close programs, disable virtual memory paging, upgrade to SSD |
| Long Boot Time | Disable startup programs (msconfig), check for malware, defragment HDD, clean temp files, verify fast startup enabled |
| Application Freezing | Check resource usage, update application, verify sufficient RAM, scan for conflicts, reinstall application |
8.2 Performance Monitoring Tools
- Task Manager: Real-time CPU, memory, disk, network usage; identify resource-heavy processes
- Resource Monitor: Detailed per-process resource usage; CPU, memory, disk, network tabs with granular data
- Performance Monitor: Create custom data collector sets; track specific counters over time; baseline performance
- Reliability Monitor: Track system stability; view crash history, Windows updates, application installs/failures
8.3 Optimization Techniques
- Disable visual effects: System Properties > Advanced > Performance Settings > Adjust for best performance
- Adjust virtual memory: Set custom size (1.5x RAM for initial, 3x RAM for maximum)
- Disable unnecessary services: Services.msc, identify and disable unused services (use caution)
- Clean temporary files: Disk Cleanup, %temp% folder, prefetch folder, browser cache
- Defragment HDD: Built-in defragmenter, schedule weekly, not needed for SSD
- Update drivers: Display, chipset, network drivers from manufacturer
- Manage startup programs: Task Manager > Startup tab, disable unnecessary programs
- Enable ReadyBoost: Use USB flash drive as additional cache (for systems with <4gb>
9. Troubleshooting Methodology
9.1 Standard Troubleshooting Steps
| Step | Actions |
|---|---|
| 1. Identify the Problem | Gather information, question user, identify symptoms, determine recent changes, duplicate problem if possible |
| 2. Establish Theory | Create list of probable causes, consider obvious first, question the obvious, start with easy fixes |
| 3. Test Theory | Test most probable cause, if confirmed move to next step, if not confirmed establish new theory or escalate |
| 4. Establish Plan of Action | Create action plan, identify potential effects, get approval if major change, consider corporate policies |
| 5. Implement Solution | Apply fix, verify access and permissions, implement preventive measures, follow best practices |
| 6. Verify Functionality | Confirm full system functionality, verify user satisfaction, test related systems, implement preventive measures |
| 7. Document Findings | Record problem description, solution implemented, lessons learned, add to knowledge base |
9.2 Best Practice Approaches
- Always back up data before making changes
- Document all steps taken and results
- Change one variable at a time to isolate cause
- Work from simple to complex solutions
- Verify environmental factors (heat, power, physical connections)
- Question the user to gather complete information
- Consider recent changes (software, hardware, updates)
- Use known-good components to test by substitution
- Search vendor knowledge bases and forums
- Don't assume - verify each hypothesis
9.3 Information Gathering Questions
- When did the problem start?
- Has this ever worked before?
- What changed recently? (updates, new software, new hardware)
- Can you reproduce the problem?
- Does it happen with all users or just specific accounts?
- What error messages appear? (exact wording)
- Does it occur at specific times or randomly?
- Have you tried restarting?
- Are other systems affected?
10. Blue Screen of Death (BSOD)
10.1 Common BSOD Stop Codes
| Stop Code | Meaning & Solution |
|---|---|
| IRQL_NOT_LESS_OR_EQUAL | Driver accessing improper memory; update/rollback drivers, check for hardware conflicts, test RAM |
| PAGE_FAULT_IN_NONPAGED_AREA | Bad RAM or driver issue; run memory diagnostic, update drivers, check disk errors |
| SYSTEM_SERVICE_EXCEPTION | Driver or system service error; update drivers, run sfc /scannow, check Event Viewer |
| KMODE_EXCEPTION_NOT_HANDLED | Kernel-mode driver error; update drivers, especially graphics and network, check for malware |
| BAD_POOL_HEADER | Memory allocation error; test RAM, update drivers, scan for malware, check disk |
| CRITICAL_PROCESS_DIED | Essential system process terminated; run sfc /scannow, check for corrupt system files, restore system |
| DPC_WATCHDOG_VIOLATION | Driver timeout; update firmware and drivers, check for hardware conflicts, disable fast startup |
| DRIVER_POWER_STATE_FAILURE | Driver power management issue; update drivers, disable fast startup, check power settings |
10.2 BSOD Troubleshooting
- Note exact stop code and any listed file names
- Check Event Viewer (System log) for details before crash
- Boot to Safe Mode to isolate driver issues
- Use Driver Verifier to identify problematic drivers
- Run memory diagnostic (Windows Memory Diagnostic or Memtest86)
- Check for overheating (CPU/GPU temperatures)
- Update or rollback recently changed drivers
- Run chkdsk /f /r to check disk integrity
- Test with known-good hardware components
- Analyze minidump files with debugging tools (WinDbg, BlueScreenView)
10.3 Analyzing Memory Dumps
- Minidump location: C:\Windows\Minidump
- Configure dump settings: System Properties > Advanced > Startup and Recovery > Settings
- Use BlueScreenView or WinDbg to analyze dumps
- Identify driver or process causing crash
- Research stop code specific to error
11. Licensing and Activation Issues
11.1 Windows Activation Problems
| Issue | Resolution |
|---|---|
| Windows Not Activated | Enter valid product key, use activation troubleshooter, verify internet connection, reactivate after hardware change |
| Activation Error 0xC004F074 | KMS server not found; check DNS, verify network connectivity, ensure KMS server running |
| Hardware Change Deactivation | Use activation troubleshooter, link Microsoft account to license, select "I changed hardware recently" |
| Invalid Product Key | Verify key matches Windows edition, check for typos, ensure key not already used on maximum devices |
| Activation Server Unavailable | Check internet connection, wait and retry, activate by phone, verify firewall not blocking activation |
11.2 Office Activation Issues
- Not activated: Sign in with Microsoft account, verify subscription active, run activation troubleshooter
- Multiple activations: Sign out of Office on unused devices, deactivate from account portal
- Subscription expired: Renew Microsoft 365 subscription, verify payment method valid
- Unlicensed product: Activate Office, verify product key, check Office version matches key type
11.3 Software Licensing Issues
- Volume licensing: Ensure KMS/MAK key configured, verify activation count, check with license server
- Downgrade rights: Verify license includes downgrade rights, install appropriate edition
- License compliance: Track installed software, verify count matches purchased licenses, use asset management tools
- Transfer license: Uninstall from old device, deactivate if required, install on new device with same key
12. Command Line Tools
12.1 Essential Windows Commands
| Command | Usage |
|---|---|
| sfc /scannow | Scan and repair system files; requires elevated command prompt, may need installation media |
| DISM | Repair Windows image; /Online /Cleanup-Image /RestoreHealth (repairs component store) |
| chkdsk /f /r | Check disk for errors; /f (fixes errors), /r (recovers bad sectors), requires reboot for system drive |
| bootrec | Repair boot configuration; /fixmbr, /fixboot, /scanos, /rebuildbcd (from Recovery Environment) |
| diskpart | Disk partition utility; list disk, select disk, clean, create partition, format, assign letter |
| gpupdate /force | Force Group Policy update; immediately applies new policies without waiting |
| shutdown | Shutdown or restart; /s (shutdown), /r (restart), /t XX (delay seconds), /f (force close apps) |
| taskkill | Terminate process; /IM name.exe (by image name), /PID #### (by process ID), /F (force) |
| tasklist | List running processes; /svc (shows services), /v (verbose) |
| systeminfo | Display system information; OS version, install date, hardware details, patches installed |
12.2 File and Directory Commands
| Command | Function |
|---|---|
| dir | List directory contents; /a (show hidden), /s (include subdirectories), /p (page by page) |
| cd | Change directory; cd\ (root), cd.. (parent), cd foldername (navigate to folder) |
| copy | Copy files; copy source destination, /y (suppress overwrite prompt) |
| xcopy | Advanced copy; /s (copy directories), /e (include empty), /h (copy hidden/system files) |
| robocopy | Robust file copy; /mir (mirror), /e (include empty dirs), /mt (multi-threaded), /log (create log) |
| del | Delete files; /f (force), /s (subdirectories), /q (quiet mode) |
| attrib | Change file attributes; +r (read-only), +h (hidden), +s (system), -attribute (remove) |
| md/mkdir | Make directory; creates new folder at specified path |
| rd/rmdir | Remove directory; /s (remove all), /q (quiet mode) |
12.3 Registry Commands
- reg query: Query registry values; reg query HKLM\path /v valuename
- reg add: Add registry entry; reg add HKLM\path /v name /t type /d data
- reg delete: Delete registry entry; reg delete HKLM\path /v valuename /f
- reg export: Export registry key; reg export HKLM\path filename.reg
- reg import: Import registry file; reg import filename.reg
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Apr 20, 2026 Last updated
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