Rebooting ?

Cannot reboot a Phillips computer from a black screen with writing on it (from when you switch it on) asks to exit set up del or press F9 to reboot i think.Will not do either. It goes through many screens slowly and then asks for recovery disc which my friend no longer can find. Is it really knackered or will the disc solve the problem.
I am no good at computers, I prefer nursing as my chosen career, so if anyone can help thanks a million. I can fix people, just not PC's !!!!