CCleaner can be downloaded from www.download.com, go to the search bar and type in ccleaner. The former name for ccleaner was Crap Cleaner and that is pretty much what it does.

CCleaner finds log files and temporary files which are created as a part the normal day to day use of a computer but mostly from Internet activity. Your computer keeps a copy of images and files downloaded and sometimes those files can become hundreds of megabytes of information. Your computer checks those files to see if they have relevance to a current search and in so doing can waste a lot of computer cycles. Using CCleaner every few weeks will keep your computer up to speed.

What you might want to avoid is checking anything but the default settings on ccleaner. To check the advanced setting boxes could lead to the loss of important information.