My Screen Turns off on Startup Please help

[Homer34s]

I'm new to this site but have always got good info from it. I hope some1 can help me out with this problem.

I have Windows Vista and when I startup my computer everything is fine right before the windows symbol comes out and then my screen just goes black. If i turn off and turn on my screen I can use my computer fine for 5 seconds and then it goes black again. I have to restart my computer 2 to 3 times for it to work fine. I'm not sure what to do I checked my anti-virus it was fine I deleted all the new stuff I downloaded just in case and no luck. I tried my system restore but it was disabled on accident so I cant use that. Any advice?

Homer34s