Sometimes, it is important to remember that backups are never out of reach.  For example, windows 7 has them built in this way:

http://www.microsoft.com/windows/windows-7/features/backup-and-restore.aspx
and, don;t forget about system checkpoints and restore options.

the Mac OS has Time machine:

http://www.apple.com/macosx/what-is-macosx/time-machine.html

And Linux has…well, linux may or may not have something built-in, depending on your build and version and what day it is.  so, go to sourceforge.net and search for open source backups…but nobody on linux will read this anyway.