Screen not responding when booting up! PSU problem?

Hello

I have a Macbook Pro from late 2008 that has been working fine since I got it but now the screen is completely black when I boot it up. Everything else seems to be working. I read about lots of people who has had the exact same problem and that they could get it fixed for free by Apple because it was a problem with the nvidia card.

Yesterday I went to an apple reseller which took in the macbook and contacted me today and said it would cost almost $1000 to get it fixed. They claim that it is a problem with the power supply and NOT the nvidia card. But I'm wondering how can it even boot up if the power supply isn't working? Is there anything else I can do?

I can't pay that much money just to get a new power supply when I can have a brand new laptop at the same price.

- Ben