CCleaner
CCleaner does double duty: Not only does it help protect your privacy, but it also keeps your system clean and running well. To protect your privacy, it removes traces of your Internet history, such as your temporary Internet files, browsing history, autocomplete form history, and cookies. In addition, it cleans Windows' Recent History list.
It's great at cleaning your system as well. CCleaner gets rid of many different kinds of unneeded files, such as temporary files, Windows log files, chkdsk file fragments and a lot more. It can also check your Registry and clean it of bad or broken entries and help you stop programs from running on start-up.
For anyone who wants to keep their browsing life private -- and keep their system clean and running smoothly -- this is a must-have download.