My 6mth (hmm maybe 9mths?) MacBook died tonight

It was acting funny this afternoon so I shut it down and when I switched it on tonight, it's not starting up. Just gives the startup tone and then nothing- completely blank screen.
Anyone got any ideas what to do? I've tried everything in the instructions book and now I'm ready to reinstall Mac OS X but not sure I want to do that. Also, before I do that I need to backup everything onto USB drive if possibly
Oh why didn't I back up????