When I start my computer this message pops up:

1962: No operating system found. Press F1 to repeat boot sequence.

I've done some looking around and I haven't found a clear answer. It started happening last night, it was weird. I was reading and I had Photoshop open, then the computer froze up, restarted and the message popped up.

Anyone know whats the problem?

BTW,
I can't find my Windows 98 disk, so that's not an option.