pc will not power up

When I press the power button, the red power led blinks and the fans spin for a split second then nothing. Pressing the power button again does nothing until I turn the power off to the pc. The the same thing happens. I replaced the power supply and get the same results.

Problem started when I was loading programs for my Canon camera from the cd that came with it. Message said pc would restart after installing program, but pc went off and never came back.

Any help would be greatly appreciated.

Thanks

Archie