The easiest way to do this is to follow this procedure:
START - PROGRAMS - ACCESSORIES - DISK CLEANUP.
Depending on your version of Windows, you will be given several options but the most important ones are Temporary Internet Files and Temporary Files. It might be a good idea to empty your Recyle Bin at the same time.

REMEMBER: Temporary Folders are just that - for temporary stuff. Don’t ever keep anything important that you might want to use again in a TEMP folder - always store it in a separate folder.