New hardware not working blues

[Gabriel Gunderson]

I had big plans to redo my home network this weekend.

After I put a new box together from the parts I purchased today, I
discovered a problem.

I get a post on the new box and I'm able to get to the BIOS and make the
changes I'd like. I can even get a few seconds into a Linux installer,
but then the PC just powers off - instantly.  This happens without fail
within 3 - 4 mins of turning on the system.

The PC will not boot back-up right away.  If I let it sit for about 2-3
min. and toggle the switch on the back of the power supply to off, then
in a few seconds I'll hear a very faint noise like "pssss".  I can't
really tell where the sound is coming from.  After it makes that noise,
I flip the switch on the back and it will power up for a few more
minutes before doing the same thing again.

Nothing looks out of place, the heat sink on the CPU feels cool, and I
don't smell any smoke.  I removed all of the cards and drives so that I
could eliminate them.  It still does it with just the motherboard, CPU,
memory and whatever else is needed to power-up.

It's 2:30 am, I'm sleepy, and I feel like I'm rambling.  Please lend
your wisdom and save my weekend.

Good Night,
Gabe