Here are a couple of handy freeware apps that I use for system maintenance. Very nice little utilities. One caution, if you use the default settings it will delete your browser history.

http://iobit.com/advancedwindowscareper.html?Str=download

If you want to schedule automatic defrags on your system, try Smart Defrag here:

http://iobit.com/iobitsmartdefrag.html?Str=download