Disable Windows Indexing

The Windows Indexing Service is always running in the backround on your PC and can use a noticable amount of your CPU. This will make your hard drive run faster at the cost of a little bit slower search when you do a windows search.

To do this, open up "My Computer", Right Click on C:, Click properties, Uncheck "Allow Indexing Service to index this disk for fast file searching", click ok.

Clean Up Your Registry
Defragment Your Hard Drive
Run a Virus Check