Well I bought all my computer parts and I was planning too build a computer and I got all the stuff... and I hooked it all up right ...I believe and I went too turn it on and it looks like it turns on for half a second and turns off right away. The front of the case and my led key board whats hooked up just flash kinda and my fans start too spin for a second then everything jsut dies.

I thought it might be the PSU so i brought it back and got a 700watt one over the 600one i had and still the same thing.

The motherboard is a Asus P5n-e SLI
Processor is a e6700
1 harddrive
1 optical drive
1 8800gts
2Gigs of Ram

I could be wrong in your case but I've seen this like 10 or 15 times everytime it was caused by poor installion of the MOBO.

Did you use the all standoff's and all the screws you were supposed to ?

I had a friend with an socket A MOBO get lazy and not use the standoff's at all, Had exaclty the same symptoms.
He RMA'd his board got the new one and guess what? Exact same thing happend.

Once I went around and put the standoff's in and all the screws it fired up straight away,Make sure you have all the screw's and standoff's tightend well(not too much though) and that the board is nice and level so that one end is touching the case or something.

Sorry about the length of the post but I really think its cause by a short/poor ground rather then a dead MOBO.

The only reason I disagree with you is because the OP says it turns on for only a second, then turns off. Now, if it were on for a minute or two, I would be inclined to believe you. However, I don't think a CPU (C2D specifically) can overheat in a matter of 2 secs.

IMO, I think it sounds like a poor installation of the mobo/connections. It isn't on long enough for any other component to cause a failure. Even without RAM a mobo will POST an error, but will still stay on. You can power on a mobo with absolutely nothing in it and it should stay on.

My suggestion is to break down the entire build and build it up one piece at a time. First, use only the mobo and PSU. Turn it on and wait for a beep code or some sort of error message. Then, install the CPU and heatsink and repeat the test. Then memory, test that. Then video card, test that. Then hard drive, test that. Leave ALL non essentials off (sound cards, etc.) during testing until the very end.

alright guys thanks for the help ill try it and sorry for posting in overclocking i didn't notice that.

Apparently a mod moved it. It's no big deal, the reason people are anal about it is some people stick to only their section (alot of the experts do).

Keep us apprised.

Edit: damn typos!

Make sure your CMOS reset jumper is in the correct position, and while you're there, clear the CMOS for a few seconds to eliminate that from the list. Make sure your memory sticks are fully seated. The clips on the ends should be perpendicular to the board.