[cbloom]

BTW re-installing windows for this is like putting up pictures with a sledgehammer.

Defrag the disk.

Make sure you aren't running a lot of software you don't want. Just go to "Add/Remove Programs" and uninstall anything you don't use or you don't recognize.

Run "Adaware" and tell it to delete everything it finds.

Run a good antivirus with rootkit search (like AVG).

Run a startup inspector, I like "Startup Control Panel" but there are many. Look at all the junk in there and disable anything that looks funny. This is a semi-expert step the other steps are quite easy.

Also I would back up anything important before doing anything severe to a machine, you don't need to back up your programs just your data.