I work in IT, used to work in a computer shop, 9 times out of 10 the customer wouldn't have a backup. Often you can get files back but not if the harddrive is completely dead,. Had to deliver the news several times to customers who generally felt is was our fault that they had lost their data!!

I also remember a funny story of a customer having a backup on discs, but they'd used a backup program to make the backup rather than copy the files. When the PC died and was replaced or repaired i got the discs from them but they didn't know what program they'd used to create the backup so I couldn't restore it! Tried heaps, eventually gave up!