Windows 11 has several built-in diagnostic tools, and the right one depends on the problem. For a quick overall health report, press Windows + R, type perfmon /report, and press Enter to generate a System Diagnostics report in about a minute. To test RAM, run mdsched.exe (Windows Memory Diagnostic). To check and repair Windows system files, run sfc /scannow and DISM /Online /Cleanup-Image /RestoreHealth in an administrator Terminal. To check a drive, run chkdsk C: /scan. Reliability Monitor (perfmon /rel) shows a timeline of crashes and errors.
This guide explains each tool, when to use it, how to read the results, and how to run your PC maker’s hardware diagnostics for deeper tests.
Quick reference
| Problem | Tool | How to open |
|---|---|---|
| General slowness or errors | System Diagnostics report | perfmon /report |
| Crashes, freezes, app errors over time | Reliability Monitor | perfmon /rel |
| Random crashes or blue screens | Windows Memory Diagnostic | mdsched.exe |
| Corrupted Windows files | SFC and DISM | Terminal (Admin) |
| Drive errors or slow disk | CHKDSK and drive health | Terminal (Admin), Settings |
| Laptop battery life | Battery report | powercfg /batteryreport |
| Hardware faults | PC maker’s diagnostics | Manufacturer app or startup menu |
1. Generate a System Diagnostics report
- Press Windows + R, type perfmon /report, and press Enter. Approve the admin prompt.
- Wait about 60 seconds while Performance Monitor collects data.
- Review the Diagnostic Results section at the top. Warnings are marked with red or yellow icons and include suggested fixes.
- Expand sections like Hardware Configuration, CPU, Disk, and Memory for details.
2. Check Reliability Monitor
Press Windows + R, type perfmon /rel, and press Enter. The graph rates stability from 1 to 10 each day. Red X icons mark critical events like app crashes and Windows failures; click a day to see details. This is useful for spotting when problems started, such as after a driver or update.
3. Test your memory (RAM)
- Save your work.
- Press Windows + R, type mdsched.exe, and press Enter.
- Click Restart now and check for problems.
- The PC restarts and runs the test, which can take 10 to 30 minutes or longer. Press F1 during the test for options like the Extended test.
- After Windows starts, results may appear as a notification. If not, open Event Viewer > Windows Logs > System and filter for the source MemoryDiagnostics-Results.
4. Repair system files with SFC and DISM
- Right-click Start and choose Terminal (Admin).
- Run
DISM /Online /Cleanup-Image /RestoreHealthand wait for it to finish. It repairs the Windows image that SFC uses. - Run
sfc /scannow. When it finishes, it reports whether it found and fixed corrupted files. - Restart the PC.
5. Check your drives
- Scan for file system errors – run
chkdsk C: /scanin Terminal (Admin). If it finds problems, runchkdsk C: /f, which schedules a repair at the next restart. - Check drive health – go to Settings > System > Storage > Advanced storage settings > Disks & volumes, select a drive, and click Properties. NVMe SSDs show estimated remaining life, available spare, and temperature.
- Quick status – run
Get-PhysicalDisk | Select FriendlyName, HealthStatus, OperationalStatusin PowerShell.
6. Generate a battery report (laptops)
- Open Terminal and run
powercfg /batteryreport. - Open the HTML file it creates (the path is shown, usually in your user folder).
- Compare Design Capacity with Full Charge Capacity. A much lower full charge capacity means the battery has worn.
For sleep and power problems, powercfg /energy creates a report of power efficiency issues.
7. Run your PC maker’s hardware diagnostics
For deeper hardware tests, use the manufacturer’s tool. Many PCs include diagnostics you can start from the boot menu (often by pressing F2, F12, or Esc at startup) or from an app such as HP PC Hardware Diagnostics, Dell SupportAssist, or Lenovo Vantage. These can test the CPU, memory, storage, fans, and battery outside Windows.
Other helpful tools
- Task Manager (Ctrl + Shift + Esc) – see what’s using CPU, memory, disk, and network right now.
- Resource Monitor (resmon) – detailed per-process activity.
- DirectX Diagnostic Tool (dxdiag) – graphics and sound information and problems.
- Get Help troubleshooters – Settings > System > Troubleshoot > Other troubleshooters for audio, network, printers, and more.
- System Information (msinfo32) – a full list of hardware and drivers.
Frequently asked questions
How long does Windows Memory Diagnostic take?
The standard test usually takes 10 to 30 minutes, depending on how much RAM you have. The extended test can take hours.
Is it safe to run SFC and DISM?
Yes. They only replace damaged Windows files with correct versions.
Do these tools work on Windows 10?
Yes. All of these tools are also in Windows 10.
Kermit Matthews is a freelance writer based in Philadelphia, Pennsylvania with more than a decade of experience writing technology guides. He has a Bachelor’s and Master’s degree in Computer Science and has spent much of his professional career in IT management.
He specializes in writing content about iPhones, Android devices, Microsoft Office, and many other popular applications and devices.