Take this story as a warning, and don't forget that there are many other ways you could lose your files forever.
For example, you could drop your laptop in the harbour (it happens!); a thief couldrun off with your computer (it happens!); or you could entrust your files to a cloud service that suddenly shuts down (it happens!).
The endgame is the same in all cases: if you have a reliable and recent backup, you'll have a good chance of recovering without too much trouble.
Prevention, in this case, is significantly better than cure:
Don't forget that services that automatically synchronise your data changes with other servers, for example in the cloud, don't count as backup.
They may be extremely useful, but they tend to propagate errors rather than to defend against them.
with thanks to the great team at http://nakedsecurity.sophos.com