CCleaner (Crap Cleaner) is a freeware system optimization and privacy tool that removes unused files from your system. It allows Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. But the best part is that it’s fast (normally taking less that a second to run) and free.

You can also use CCleaner to uninstall applications and set which programs are to run at startup.

CCleaner cleans:

• Internet Explorer: Temporary files, URL history, cookies, Autocomplete form history, index.dat.
• Firefox: Temporary files, URL history, cookies, download history.
• Opera: Temporary files, URL history, cookies.
• Windows: Recycle Bin, Recent Documents, Temporary files and Log files.
• Registry cleaner: Advanced cleaner to remove unused and old entries, including File Extensions, ActiveX Controls, ClassIDs, ProgIDs, Uninstallers, Shared DLLs, Fonts, Help Files, Application Paths, Icons, Invalid Shortcuts and more… also comes with a comprehensive backup feature.
• Third-party applications: Removes temp files and recent file lists (MRUs) from many apps including Opera, Media Player, eMule, Kazaa, Google Toolbar, Netscape, MS Office, Nero, Adobe Acrobat, WinRAR, WinAce, WinZip and many more…

CCleaner is free and contain no Spyware, Adware, you can download it from http://www.ccleaner.com/download.