Every year, millions of people pay for "PC cleaner," "driver updater," and "system repair" tools that do things Windows already does for free. Worse, many of those tools bundle adware or break things they were supposed to fix.
Windows has shipped with powerful diagnostic and repair commands for decades. They are hidden inside Command Prompt, which is why most people never find them. Here are 12 of the highest-value ones—what they replace, how to run them, and when to use each.
Before you start: Open Command Prompt as Administrator for every command below. Press Start, type cmd, right-click Command Prompt, and select Run as administrator.
1. sfc /scannow — Replaces Paid System Repair Tools
Scans every protected Windows system file and replaces any that are corrupted or missing.
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sfc /scannow
Use it when apps crash randomly, Settings refuses to open, or you see missing-DLL errors. It takes 5–15 minutes and is completely safe.
2. DISM — Replaces Windows Repair Discs
Repairs the component store—the master copy of Windows files that SFC uses as its repair source.
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DISM /Online /Cleanup-Image /RestoreHealth
Run this before sfc /scannow. If the repair source is damaged, SFC has nothing to repair from. This is the single biggest reason people run SFC and still see errors.
3. resmon — Replaces Paid RAM Cleaners
Opens Resource Monitor, which shows exactly how much Private memory each process is using—the real number Task Manager hides.
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resmon
Sort the Memory tab by Private to instantly find the app eating your RAM. "RAM boosters" are almost always unnecessary; the real fix is finding the culprit process.
4. chkdsk — Replaces Disk Checker Utilities
Scans your hard drive or SSD for file system errors and bad sectors, then repairs them.
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chkdsk C: /f /r
This runs on next reboot. The /f flag fixes errors, /r locates bad sectors and recovers readable data. Do not skip backups before running /r on a failing drive.
5. powercfg /batteryreport — Replaces Battery Diagnostic Apps
Generates a full HTML report on your laptop battery: design capacity, current capacity, cycle count, and usage history.
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powercfg /batteryreport
The report is saved automatically—usually to C:\Users\YourName\battery-report.html. Open it in any browser. If "Current capacity" is far below "Design capacity," your battery is genuinely worn out. No guessing required.
6. netsh wlan show profile — Replaces Wi-Fi Password Recovery Tools
Shows every Wi-Fi network your PC has ever connected to—and reveals the saved password.
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netsh wlan show profile name="NetworkName" key=clear
Look for the Key Content line under Security settings. No third-party password tool needed, and nothing leaves your machine.
7. ipconfig /flushdns — Replaces Network Fixers
Clears the DNS cache, which fixes "site won't load" errors caused by stale or poisoned DNS records.
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ipconfig /flushdns
Follow up with:
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ipconfig /release ipconfig /renew
If your internet works on your phone but not your PC, this sequence fixes it more often than reinstalling network drivers.
8. tasklist /svc — Replaces Process Manager Add-ons
Lists every running process along with the Windows services inside each one.
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tasklist /svc
Useful for finding which svchost.exe is responsible for a service behaving badly. To kill a specific process:
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taskkill /PID 1234 /F
Replace 1234 with the actual PID from the list.
9. cleanmgr /sageset:1 — Replaces Disk Cleanup Apps
Opens the deep Disk Cleanup configuration. Most "cleaner" apps offer far less than this does.
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cleanmgr /sageset:1
Check every category you want cleaned, click OK, then run:
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cleanmgr /sagerun:1
The /sageset flag lets you configure once and reuse it forever.
10. systeminfo — Replaces System Info Tools
Prints your OS version, build number, RAM, CPU, BIOS version, boot time, and installed hotfixes in one output.
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systeminfo
To see only hotfixes:
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wmic qfe list brief
Useful for checking whether a specific security patch is installed—or when a support forum asks for your build number.
11. driverquery /v — Replaces Driver Updater Scanners
Lists every installed driver, its version, date, and status. No download, no "upgrade to premium" prompt.
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driverquery /v /fo table
Important: driver updaters are one of the most common sources of malware and broken systems. If Windows Update is not offering a driver, you almost never need it. Check the manufacturer's site directly for graphics drivers.
12. netsh int ip reset — Replaces Network Reset Wizards
Resets the entire TCP/IP stack to default—the nuclear option for stubborn network problems.
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netsh int ip reset netsh winsock reset
Reboot after both. This fixes a long list of connectivity issues that survive every other fix, and it is exactly what the GUI "Network Reset" button does.
The Rule of Thumb
If a paid tool's pitch is "clean," "optimize," "boost," or "update," check whether Windows already does it. In almost every case, it does—and it does it without ads, bundled toolbars, or a subscription.
Bookmark this page. When your PC misbehaves, run the command before you open your wallet.
Quick Reference
sfc /scannow DISM /Online /Cleanup-Image /RestoreHealth resmon chkdsk C: /f /r powercfg /batteryreport netsh wlan show profile name="NetworkName" key=clear ipconfig /flushdns tasklist /svc cleanmgr /sageset:1 systeminfo driverquery /v /fo table netsh int ip reset