i think my computer broke? calling all computer gurus!

[t-maxxracer32]

hey guys i have a fairly expensive gaming computer that was bought off a freind and its been running clean for probably 6 months for me and about the same for him.

edit. if it matters...
nvidia 6800 video card (old big ones)
2 gigs of ram
160 gig hardrive (with about 20 gigs left)
anything else that matters?

i never really shut off the computer i just let it idle at night while playing music...

last night when i got home from work everything was fine i looked through some things on the internet and left it on as i usually do.

this morning i wake up and the computer is off.... noone ever touches my computer so they would not have turned it off.

i go to turn it back on and it powers up fine but i have no signal on my monitor.

so i take off the case and start checking components. maybe somehow something got loose? well thats not the case.. everything was fine. i then unplugged all the components (power cord monitor plug usb.. etc) and waited a good 10 minutes and still nothing.

when i boot up the computer it makes the usual murmurs but after about 15 seconds it seems to stop... all i can hear are the fans. it is a quick computer so it does boot up to the welcome screen in about that time...

my question is what the hell is wrong!!

i have a couple crappy video cards i can throw in there to see if it will help but i figured before i do that type of stuff id ask you guys. i know some of you have computer smarts (arct1)

thank for any help!