Eraser

Eraser is an advanced security tool for Windows which allows you to completely remove sensitive data from your hard drive by overwriting it several times with carefully selected patterns. 


Eraser is currently supported under Windows XP (with Service Pack 3), Windows Server 2003 (with Service Pack 2), Windows Vista, Windows Server 2008, Windows 7 and Windows Server 2008 R2.

Eraser doesn't tune up Windows as much as it clears the way for your hard drive to work better. It does this by over-writing the "empty" areas of a drive you thought were deleted. Even if you empty the recycle bin, the data might still be recoverable, for example. Eraser makes sure it isn't, and that also helps with hard disk performance.