Ok, heres one for you. About a week ago my pc abruptly shutdown, I initially thought we had a power cut (we didn't) while browsing the web. Since then after that my pc wont boot, fans turn, no power button light (nothing), no beep codes. Tried the removing components and booting and nothing (fans spin, no light on power button), HDD's (2) move, took out and put back in cmos button. Cpu does not heat up (at all). This and no power button light from what I read on other forum posts on other websites led me to getting a new motherboard assuming it was that, based on replies to a post I saw that had very similar issues to mine. That didn't work, still same issue. Motherboard I bought came with cpu, switched cpu and same result. With no beep codes, removing components and booting with nothing, and fans spinning, I am lost as to what it is.
Are you using a separate graphics card, or the motherboard's graphics processor? If you have a separate graphics card, and you play games, that is when the card is likely to become power-hungry. A lot depends on the card.