Check yer backup : Lifehacker
More often than not, we never back-up. Yet, in the digital age, crucial information might thus be exposed to harm, theft, loss, permanent damage....
However, if you do backup regularly, try to check those files once in a while: they might have stopped working. Old floppies, olf cd's, old data files might not be working properly.... and it might be really expensive to restore this data: so get to work on an organized method!
