New PC won't boot...

I had a bunch of spare parts left over from a AMD 3400 build I did a while ago, and decided to put them in a new case and use it as a spare pc or whatever. I put it together and when I turn it on and hit the power button it lights up for a second and I hear the fans start to spin and it shuts off right away. It doesn't stay on long enough to get to the post screen, just stays on for about 1 second and shuts off. If you hit it again it just does the same thing. All connectors inside I'm pretty sure I have correct, this is the 3rd PC I put together and I haven't had a problem like this one before.
I reused all the same stuff that had been together in another case, power supply, mobo etc that had been working together fine a few weeks ago when I took it a part. The only things different are an older CDR drive instead of a DVD drive and I didn't have a spare floppy so I didn't put one in yet.

tried unplugging stuff but it didn't help, in fect it wouldn't do anything. I tired putting evreything back and now it won't even flash the power light like it did before....does nothing.

Maybe you have a heat problem and your PC Shut off Because the CPU temps are Very High

yes the 9 screw in stands are in there properly. I guess I'll try it out of the case. So should I leave the hard drive unhooked too just to see if it will get to the post screen?

You might try reviewing this document. Good info. http://www.tomswiki.com/page/Troub [...] ild?t=anon

Well I got it running, it seems the screws I used to hold down the motherboard wern't the right ones, these had a rather large head on them that may have shorted something on the printed circuit of the board. I used some smaller ones and it booted up OK. Thanks for the help.