Why is my computer screen black?

Whenever i try to start up my computer it just goes to a black screen why? And how do i fix it?

• It takes me to the black screen where it gives me the choices to start up in safe mode, safe mode with networking, safe mode with command prompt or start window normally. i tried start windows normally first but it just took me to a black screen with nothing but my mouse. i thought maybe it would start up after a while i waited at least 30 minutes and it didn't do anything it just stayed at the same black screen. so then i tried safe mode after that and it did the exact same thing. its a new computer i haven't even had it for a year yet. is there a way to fix this? please help me (its a gateway computer with windows vista)

• Answer:

  I know this sounds a bit simple but have you tried disconnecting your computer at the wall altogether. Leave it for a few minutes and plug it in again and try starting it again. If you have already done this then i'm sorry i didn't help. Good luck.