No power (worked randomly once)...

[Vileunknown]

I am building a new PC and have done everything correctly. When I try to boot it up it simply does...nothing. The power supply does work (used paperclip). At COMPLETE random power ran through it, then after about 5-7 seconds it turned off again...WTF. Plz help I have alrdy sent back for a new motherboard AND case. I donno what to do.

 

[AdamNesvick]

how is your motherboard mounted? you DID use the standoffs?

I'm not being an ass, but I've seen people do this before, it sounds like some kind of short.
see if the board will power up outside the case.

 

[jpmkm]

Definitely sounds like a shorting issue. Perhaps you can take everything out of the case and power it up that way. Try powering up with just the processor, memory, and video card.

 

[GlobalFear]

All the symptoms of a short. Remove everything from the case and try booting as jpmkm suggested.