Also try a program called CleanUp!
This scans through your hard drive and deletes all temporary.
It will run a test run the first time you use it (to show how much space you're currently wasting with temporary files)
What it does : "This includes things such as removing "MRU lists" (storing a list of your Most Recently Used files) for various applications, emptying the Recent Documents folder, deleting entries from the Run and Find Computer dialogs, emptying Recycle Bins, emptying temporary folders, removing some unneeded registry entries, optionally resetting the high scores for Windows games, and more."
I have run it and my computer starts up alot quicker and now runs smoother.