Well I'm not sure about clearing the Temp. But if you want to remove unused stored data etc. You should download ccleaner. click This program works great, and can clear alot of junk off a computer.
buzz just run a program called ccleaner it will remove all the stuff for you and tell you how much its getting you will be very suprised the first time you run it just how much crap it deletes
*edit* sorry for duplicate jtm posted just as i was responding i guess