CCleaner

CCleaner is a freeware PC optimization tool.
It combines a system cleaner that removes unused and temporary files from your system and also a fully featured registry cleaner!
CCleaner allows Windows to run faster, more efficiently and gives you more hard disk space.
The best part is that it's Small, Fast and Free!

Cleans the following:

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 features 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 Media Player, eMule, Kazaa, Google Toolbar, Netscape, MS Office, Nero, Adobe Acrobat, WinRAR, WinAce, WinZip and many more...

100% Spyware FREE
This software does NOT contain any Spyware, Adware or Viruses.