Why Is My Windows PC Running Slow? Here's How to Fix It

Few things are more frustrating than a computer that used to run fine but has gradually become sluggish. Before you consider buying new hardware, work through these fixes — most slow PCs can be significantly improved with software changes alone.

1. Check What's Using Your Resources

Open Task Manager (press Ctrl + Shift + Esc) and click the Processes tab. Sort by CPU and Memory usage. If something unexpected is eating resources, that's your first clue.

  • A web browser with many tabs open is a common memory hog
  • Antivirus scans can temporarily spike CPU usage
  • Background update processes (Windows Update, software updaters) can slow things down during runs

2. Disable Startup Programs

Many programs add themselves to your startup list, causing slow boot times and background resource drain. To fix this:

  1. Open Task Manager → click the Startup apps tab
  2. Review the list and disable anything you don't need launching at boot
  3. Common culprits: Spotify, Discord, OneDrive, Teams, Steam, Adobe updaters

Disabling a startup program doesn't uninstall it — it just stops it from auto-launching.

3. Free Up Disk Space

Windows needs free space on your system drive to operate efficiently. If your drive is nearly full, performance suffers. Aim to keep at least 10–15% of your drive free.

  • Run Disk Cleanup (search for it in the Start menu) to remove temporary files, old Windows updates, and the Recycle Bin
  • Use Storage Sense (Settings → System → Storage) to automate cleanup
  • Uninstall programs you no longer use (Settings → Apps)

4. Check for Malware

Malware is a common culprit for sudden performance drops. Run a full scan with Windows Defender (built into Windows — no third-party antivirus needed for most users). For a second opinion, the free version of Malwarebytes is a trusted tool for on-demand scanning.

5. Update Windows and Drivers

Outdated drivers — especially GPU drivers — can cause poor performance and instability. Check:

  • Windows Update (Settings → Windows Update) — install pending updates
  • GPU drivers: Download the latest from NVIDIA, AMD, or Intel's website directly
  • Chipset and storage drivers: Check your motherboard or laptop manufacturer's support page

6. Adjust Power Settings

Windows may be throttling your PC to save power. Go to Settings → System → Power & sleep → Additional power settings and switch to Balanced or High Performance mode.

On laptops, make sure you're plugged in when doing demanding tasks — most laptops reduce performance on battery.

7. Check Your Storage Drive Health

If your PC has an older HDD (hard disk drive), it may be the bottleneck. HDDs are dramatically slower than SSDs. Upgrading to an SSD is one of the single most impactful hardware upgrades you can make.

To check drive health, use the free tool CrystalDiskInfo, which reads your drive's S.M.A.R.T. data and flags potential failures.

8. Consider a Fresh Windows Install

If nothing else works and your PC is years old with accumulated software, a clean reinstall of Windows can restore it to near-new performance. Windows 11 and 10 both offer a "Reset this PC" option (Settings → System → Recovery) that can reinstall Windows while optionally keeping your files.

Summary Checklist

  1. Check Task Manager for resource hogs
  2. Disable unnecessary startup programs
  3. Free up disk space with Disk Cleanup
  4. Scan for malware
  5. Update Windows and drivers
  6. Switch to a better power plan
  7. Check drive health (consider upgrading to SSD)
  8. Reset Windows as a last resort