Pc Goes Black?

[rustiewood]

when i boot my pc, it comes up loads ,then in about 2 min after its up i lose everything ,monitor tells me no digital signal.now i get nothing!i can hear pc spin up ,get no audibal sounds,nothing on monitor.pc is 2.5 years old is a homebuilt.amd +3400,asues mb gt 6800 vc.anybody got any ideas?

[pam123]

OK back up a minute.
When this started happening the computer would boot and load windows as usual and then, a few minutes later the video signal would go ?
Now, you can hear the fans at start up but nothing else happens?
No beeps, etc. ?
Your power supply just went to the head of the list.
Do you have/can you borrow a spare one ?
It sounds as if yours was dieing earlier and that now it has just enough "umph" left to spin fans at start up.