The Windows Command Prompt is a powerful tool that many users overlook. With just a few simple commands, you can optimize your PC's performance, enhance security, troubleshoot issues, and maintain system health. This comprehensive guide covers the essential commands every Windows user should know to keep their computer running smoothly and safely.
Important Safety Notice
Always run Command Prompt as Administrator for these commands to work properly. Right-click the Command Prompt icon and select "Run as administrator". Some commands can affect system files, so follow instructions carefully and create a system restore point before making major changes.
System Performance Optimization
Disk Cleanup Command
cleanmgr /sagerun:1
What it does: Removes temporary files, cache, and unnecessary system files that accumulate over time and slow down your PC.
When to use: Run monthly or when disk space is low.
Clear DNS Cache
ipconfig /flushdns
What it does: Clears your DNS resolver cache, which can fix internet connectivity issues and speed up browsing.
When to use: When experiencing slow internet or website loading issues.
Check Disk for Errors
chkdsk C: /f /r
What it does: Scans your hard drive for errors and attempts to repair them. The /f flag fixes errors, and /r locates bad sectors and recovers readable information.
When to use: If you suspect disk corruption or experience frequent crashes. Requires restart.
Optimize and Defragment Drive
defrag C: /O
What it does: Defragments your hard drive for faster file access (for HDDs only, not SSDs).
When to use: Monthly for traditional hard drives. Don't use on SSDs.
View Memory Usage
systeminfo | findstr /C:"Total Physical Memory" /C:"Available Physical Memory"
What it does: Shows how much RAM your system has and how much is currently available.
When to use: To check if you need more RAM or if programs are using too much memory.
View Running Processes
tasklist
What it does: Lists all currently running processes and programs.
When to use: To identify resource-hogging applications.
Kill Unresponsive Process
taskkill /IM processname.exe /F
What it does: Forcefully closes a frozen or unresponsive program.
Example: taskkill /IM chrome.exe /F to force-close Chrome.
Security & System Protection
System File Checker
sfc /scannow
What it does: Scans all protected system files and replaces corrupted files with cached copies.
When to use: When experiencing system crashes, blue screens, or strange behavior. Takes 15-30 minutes.
DISM Repair Tool
DISM /Online /Cleanup-Image /RestoreHealth
What it does: Repairs the Windows system image and component store. Run this BEFORE sfc /scannow if that command finds errors.
When to use: When sfc /scannow reports it cannot fix certain files.
Windows Defender Quick Scan
"%ProgramFiles%\Windows Defender\MpCmdRun.exe" -Scan -ScanType 1
What it does: Runs a quick malware scan using Windows Defender.
When to use: Daily or when you suspect malware.
Windows Defender Full Scan
"%ProgramFiles%\Windows Defender\MpCmdRun.exe" -Scan -ScanType 2
What it does: Performs a comprehensive system scan for malware and threats.
When to use: Weekly or monthly deep security check.
View Active Network Connections
netstat -ano
What it does: Shows all active network connections and listening ports. Helps identify suspicious network activity.
When to use: To check if unknown programs are accessing the internet.
Reset Network Settings
netsh winsock reset
What it does: Resets network configuration to defaults, fixing many internet connection issues.
When to use: When experiencing persistent network problems. Requires restart.
Show Wi-Fi Passwords
netsh wlan show profile name="NetworkName" key=clear
What it does: Displays the saved password for a specific Wi-Fi network.
Example: Replace "NetworkName" with your actual network name.
System Information & Diagnostics
Comprehensive System Information
systeminfo
What it does: Displays detailed configuration information about your computer and operating system.
When to use: When you need to know your Windows version, processor, RAM, or other hardware details.
Check Windows Version
winver
What it does: Opens a window showing your Windows version and build number.
When to use: To verify if your Windows is up to date.
Generate Battery Report
powercfg /batteryreport
What it does: Creates a detailed HTML report about your battery's health, capacity, and usage history. Saved to C:\Windows\System32\battery-report.html
When to use: To check battery degradation on laptops.
Energy Efficiency Report
powercfg /energy
What it does: Analyzes your system for energy efficiency issues and generates a report.
When to use: To optimize battery life and power consumption.
List All Drives
wmic logicaldisk get name,size,freespace
What it does: Shows all drives, their total size, and available free space.
When to use: To quickly check storage capacity across all drives.
Check Drive Health (SMART Status)
wmic diskdrive get status
What it does: Displays the health status of all physical drives. "OK" means healthy.
When to use: Regular maintenance check to predict drive failure.
Maintenance & Updates
Check for Windows Updates
wuauclt /detectnow /updatenow
What it does: Forces Windows to check for and download available updates immediately.
When to use: When automatic updates seem stuck or delayed.
Clear Windows Update Cache
net stop wuauserv
rd /s /q C:\Windows\SoftwareDistribution
net start wuauserv
What it does: Stops Windows Update service, deletes the update cache, and restarts the service. Fixes stuck updates.
When to use: When Windows Updates fail repeatedly.
Empty Recycle Bin
rd /s /q %systemdrive%\$Recycle.bin
What it does: Permanently deletes all files in the Recycle Bin.
When to use: To free up disk space quickly.
Create Restore Point
wmic.exe /Namespace:\\root\default Path SystemRestore Call CreateRestorePoint "Manual Restore Point", 100, 7
What it does: Creates a system restore point that you can revert to if something goes wrong.
When to use: Before installing new software or making system changes.
Pro Tips
- Create a batch file: Save frequently used commands in a .bat file for quick execution
- Schedule commands: Use Task Scheduler to run maintenance commands automatically
- Document changes: Keep notes of which commands you run and when
- Test first: Try commands on a non-critical system first if possible
- Keep backups: Always maintain current backups before running system-level commands
Quick Reference Command List
Daily/Weekly Maintenance
ipconfig /flushdns - Clear DNS cachecleanmgr /sagerun:1 - Clean temporary files"%ProgramFiles%\Windows Defender\MpCmdRun.exe" -Scan -ScanType 1 - Quick malware scan
Monthly Maintenance
sfc /scannow - Check system file integritychkdsk C: /f /r - Check disk for errorswmic diskdrive get status - Check drive healthdefrag C: /O - Optimize drives (HDD only)
Troubleshooting
netsh winsock reset - Fix network issuesDISM /Online /Cleanup-Image /RestoreHealth - Repair system imagetasklist and taskkill - Manage frozen programsnetstat -ano - Check network connections
Remember
- Always create a restore point before making major changes
- Run Command Prompt as Administrator for most commands
- Some commands require a system restart to complete
- Research commands you don't understand before running them
- Keep your system backed up regularly
Conclusion
Mastering these Command Prompt commands empowers you to maintain, optimize, and secure your Windows PC like a pro. Regular use of these maintenance commands can prevent many common issues, improve system performance, and extend your computer's lifespan. Start with the basic commands and gradually incorporate more advanced ones into your maintenance routine.
Remember, the Command Prompt is a powerful tool—with great power comes great responsibility. Always double-check commands before executing them, and when in doubt, research or consult with an expert. Happy optimizing!
Written by Austin Nammack
Austin Nammack is a web development expert and PC optimization specialist at RamStar Web Development. With years of experience in system administration and performance tuning, Austin helps users get the most out of their Windows machines through practical, easy-to-follow guides.