I often see "my PC is slow how do I fix it?" questions. Here's my answer:

1. Install and run CCleaner. It will delete tons of temporary crap from your computer, which will speed up the following scans. (Less crap to scan = shorter scans.) Their downloads page has a small link to the "Other Builds" page (here). Download the "Slim" build, because it doesn't come with the Yahoo toolbar.

2. Update and scan your entire computer with your anti-virus software. Performing the scans in Safe Mode works best. If you don't have any Antivirus software, get the free edition of AVG Antivirus here.

3. Delete all but the most recent System Restore point.

4. Install and run at least one anti-spyware app. Ad-Aware SE and Spybot: Search & Destroy are two popular ones. Again, scanning in Safe More works better.

5. Defragment all your hard drives.

6. If it's still too slow, get more memory. Kahlon's website has a useful search function which tells you what kind of memory you need to buy. (You don't have to buy from them.) You should have at least 1 GB for XP, 2 GB for Vista.

7. If it's still slow, and you have a second physical hard drive (not a second partition), you can get a bit of a speed boost by moving your paging file off your system drive. (It's where Windows writes temporary information for virtual memory.) You can find a tutorial on moving it here.

8. Load up msconfig (Start -> Run -> msconfig), open the Startup tab, and disable things you don't need to load at startup. (Quicktime taskbar helper, Adobe Gamma Loader, blank entries, things that have to do with Office...) Reboot. If you experience problems running any of your programs, re-enable some processes by checking their boxes. This will reduce memory overhead and boot times.

9. Don't use file sharing programs. They're virus freeways.

10. Take your PC outside, open the case, and blow all the dust out with an air compressor or those cans of air. (You can get an air compressor tank from Harbor Freight Tools that you can refill at the gas station if you want, but for a one-time thing you're better off buying a can of air.) More dust = more heat = harder-working fans = slower PC (it slows itself to keep from overheating). It's a good idea to do this at least annually.

That's it.

Leave a comment if you found this useful, or have something to add!

Revision History:
3/3/08 - Initial Version
3/19/08 - Fixed a couple messed up links