one site i really like is http://www.bold-fortune.com . you can delete alot of unnecesary ,useless,garbage files.there are 1000's of them that are just cluttering your hd.I've done quite a few and i have noticed a good difference in speed.Also, if you can find something like Registry Mechanic,it has a feature where you can delete duplicate files.That let me delete around 1200 files that are laying around!