ccleanerDuring the course of normal operation, it is quite common for a program to create little files for its own use.  When the program terminates, it might remove these files or it might not, depending on many factors.  Over time, these temporary files (or temp files), can accumulate in different corners of your computer and take up a fair amount of disc space.  Enter CCleaner. CCleaner is a fantastic little utility for cleaning out all the little (and some not so little) temp files on a Windows system, but temp files are just the beginning.  From the CCleaner site:

Cleans the following:
Internet Explorer -Temporary files, history, cookies, Autocomplete form history, index.dat.
Firefox -Temporary files, history, cookies, download history, form history.
Google Chrome – Temporary files, history, cookies, download history, form history.
Opera – Temporary files, history, cookies.
Safari – Temporary files, history, cookies, form history.
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, Microsoft Office, Nero, Adobe Acrobat, WinRAR, WinAce, WinZip and many more…

If you run Windows, i highly recommend checking out CCleaner!

Further Reading

CCleaner Website

Youtube video walk through of CCleaner installation

Youtube video outline of CCleaner features