Best Free File Cleaner
My first choice here is CCleaner, a product that started off as pretty basic but has continued to improve to the point where it is now very close to the best in its class regardless of price. It's very effective in freeing up disk space by removing unused and temporary files, cookies, Recycle bin entries, Windows hot-fix files, old prefetch data, history and cache files in many applications such as Internet Explorer and Firefox and much more. Additionally, it will check the Windows Registry for invalid entries.
There are some minuses: first, the installation settings are quite aggressive so do check them carefully. Second, the product installation, by default, includes the installation of the Yahoo Toolbar, so if you don't want it make sure you uncheck that option. Finally, I wouldn't trust this product to do your Registry cleaning; that's a job for a specialist utility. Similarly, if your aim is to remove all your surfing traces rather than just to clean up your disk, I'd be inclined to use a specialist cache cleaner.
However, if simply freeing up disk space is your objective then CCleaner is hard to beat.
A good companion to CCleaner is Empty Temp Folders. It's not as complete a product as CCleaner and it's been a while since it was last updated, but I find that it always manages to clean more temporary files than CCleaner. That's why I suggest you use both.
Another cleaner with a solid following is Steven Gould's CleanUP!. It's compact, well designed and very well maintained and is a real alternative to CCleaner. In use I've had a couple instances which caused problems on my test PC, but this may have been specific to my setup. Certainly the feedback I get from users has been uniformly excellent.
In a related category is PC Decrapifier. Its job is to remove unwanted trial versions of programs and services that come preinstalled on new PCs. You can remove all this stuff manually, but PC Decrapifier does this automatically. It can't remove every bit of junk from every computer, but the list of products it will remove is quite impressive.
CCleanerWebsite: http://www.ccleaner.com/Download link: http://www.ccleaner.com/downloadAuthor: Piriform Ltd.Current version: 2.0.11.636Version date: August 25, 2008License: FreewareDownload Filesize: 2,851KBOperating Systems Supported: Win9x/Me/NT4/2000/2003/XP/VistaAdditional Software Required: None64 Bit Capable: NoPortable Version Available: YesNon-English languages supported: Albanian, Arabic, Bosanski, Bulgarian, Català, Cesky, Chinese (Simplified), Chinese (Traditional), Dansk, Deutsch, Español, Français, Galego, Greek, Hebrew, Italiano, Japanese, Korean, Lietuviu, Macedonian, Magyar, Nederlands, Norwegian, Polski, Português, Português (do Brasil), Romana, Russian, Serbian Cyrillic, Serbian Latin, Slovensky, Suomi, Svenska, TürkçeOther relevant information: None
Empty Temp FoldersWebsite: http://www.danish-shareware.dk/soft/emptemp/ Download link: http://www.majorgeeks.com/download1575.htmlAuthor: Finn Ekberg ChristiansenCurrent version: 2.8.3Version date: August 2001License: FreewareDownload Filesize: 651KBOperating Systems Supported: Win9x/Me/NT4/2000/2003/XP/VistaAdditional Software Required: None64 Bit Capable: NoPortable Version Available: NoNon-English languages supported: None.Other relevant information: None
CleanUp!Website: http://cleanup.stevengould.org/Download link: http://www.stevengould.org/software/cleanup/download.htmlAuthor: Steven R. GouldCurrent version: 4.5.2Version date: June 26, 2006License: FreewareDownload Filesize: 332KBOperating Systems Supported: Win9x/Me/NT4/2000/2003/XP/VistaAdditional Software Required: None64 Bit Capable: NoPortable Version Available: NoNon-English languages supported: NoneOther relevant information: None
PC DecrapifierWebsite: http://www.pcdecrapifier.com/homeDownload link: http://www.pcdecrapifier.com/downloadAuthor: Jason YorkCurrent version: 1.9.1Version date: April 30, 2008License: Free for Personal use. Commercial License available.Download Filesize: 672KBOperating Systems Supported: XP/VistaAdditional Software Required: None64 Bit Capable: NoPortable Version Available: NoNon-English languages supported: NoneOther relevant information: