Screen does not light up but computer works fine - graphics issue

Hello,

One morning turning on my machine the screen would not light up. The computer works well and I can access it through screen sharing. I think there is something wrong with the graphics card because
when I try and open iMovie the computer tells me 'Quartz Extreme Required - One or more of your graphics cards does not support Quartz Extreme'.

See photo:
http://img215.imageshack.us/img215/2858/photomar2690854fm.jpg

Problem:
- How can I run system diagnostics hardware test?
(I understand there is one on the os x disk, but I cannot see screen the screen)

- Anyone else with this problem? Any good hardware test software for OS X?

Thanks