Bit of an odd one- My friend's W7 laptop restarted and now it appears to have gone back to factory settings and all the data wiped? Is this highly unusual? Could it be a virus? Has everything actually been wiped?
Hard to say without knowing the make and model. Some laptops can be reset by holding down a key (or keys) on keyboard and while press power on button, that could possibly mean that if a key was 'stuck' it would go to the reset screen on startup.. though I would have thought it would be a menu brought up to choose from and not reset automatically. I could be wrong about that.
Have you looked at he hidden recovery partition? I heard of a case where the data somehow ended up there. You could try Easus Partition Recovery tool, which worked for me with a young relative's laptop.