Laptop turns on and off

Hello,
I recently took my computer to a technician and was charged $220 because it would turn on, but the screen wouldn't turn on. The technician said it was the motherboard, and that it was typical of Compaq HP laptop computers.

It has been a week since that happened, but now my laptop turns on and off by itself. It doesn't even make it to the Widows screen. It just turns on and off. The first time it turned off it made a beep, so I left it off. Then I tried turning it back on again, and that is when it began turning on and off.

So, I just shut the lid and left it overnight. In the morning I tried turning it back on, but now it turns on but the screen doesn't turn on.

I don't want to sound dramatic, but will someone please, please, please help me. I'm and idiot and have all my notes saved on that computer and no backups. To make things worst, my finals start tomorrow. I need the notes to study.

Your help will be much appreciated. I'm getting desperate and have resorted to begging to the computer to please turn on.