A flaky power supply would be the first place I would look to. How old a machine?
my computer had been working fine until this morning. when i hit the power button, the computer's power would be on but the computer would not boot--and there is nothing on the monitor. the computer would boot up normally only after i hit the reset button. there is no problem restarting or shutting down once it is started. DO I NEED A NEW POWER SUPPLY OR ANYTHING? and i have checked inside the box and found nothing loose there. still clueless. tia.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic