That's enough to put a damper on your day - I guess I don't need to ask if you're backed up...
Backups only matter so much for home computers. (Servers are a different matter.)
I'm in a situation similar to app103 at the moment. However, I'm far too lazy to bother with the computer at all. So... I took it in to have it repaired. (Hardware problems and all.)
New video card. New CPU fan. $100 later at the shop and it works.
Get home. Power on. Nothing. Not fun.
Backups won't help as I don't need the backup data per se. I need the machine with its configuration and installed software (that I can't install elsewhere). Again, not fun.
Hardware problems are simply evil. You cannot fix them with a bit of knowhow and elbow grease. You need parts. There's no substitute for that.
And app103, don't feel bad about not finding the model number. Hardware vendors have mystical and magical powers. In particular, they have 2 powerful spells that they use on a regular basis:
1) "Find most obtuse place to stamp model and serial" (a most sinister spell indeed...)
2) "Shrink model and serial stamp for electron microscope use only" (again, a most sinister spell...)
Dark arts indeed! These hardware people are either in league with Satan or the Chinese. I haven't figured out exactly which yet... Though I do have my suspicions!