Okay,

So I have one of these PSU's in my current PC and it works fantastically. I put one in a second PC that I'm building with some slightly older parts (Abit AV8, Radeon X800 PRO, Audigy 2 ZS, 1GB RAM). Anyways, when using some PSU that I scrapped from an old Gateway, the machine worked fine, but I was planning on not using that PSU. I ordered an OCZ GamexStream and I put it in the machine. Now, when I hit the power button, the fan LEDs light up for a quick second and then turn off. It's like the machine is being powered up for a second and then dies.

Any ideas?

Check and see if the old PSU has a -5 volt line...

The OCZ in question only has +12v +5v +3.3v 5vsb(Used when the system is off...lets some boards keep the USB ports powered) and -12v

Some older machines used an extra line -5. It has been dropped from most new PSU's....your board does not seem old enough to need ut, but it never hurts to look.

Also make sure all the cables went in tight....unplug and replug to be sure. Make sure that the 4pin CPU power went in all the way...Also it looks like your board uses the 20pin cable....you did not stick that extra 4 in the cpu power.....i hope not.....there is another cable for that....

Do you have another machine to test it on?

Wait...what?

Ok, your board has 1 atx connector(20 pin....at least from pictures of the board) and 1 cpu power connector (4 pin)

Your main power cable should have 24 pins, 4 of them separate to make it compatible with 20 pin boards. I was asking to make sure that those extra 4 did NOT get connected to the cpu (4 pin) header. since on your board they are close to one another...

4 pins come off(yours looks a little different) the main ATX connector to make it fit a 20 pin motherboard. The 4 pins extra are NOT for the cpu. they just sit there and do nothing

Your cpu power connector is a 8 pin connector that splits in 2(you need all 8 when running some newer and or server boards....)

The link below has a review with pictures of the plugs in question...

http://www.tweaktown.com/reviews/927/2

To conferm, this is your board?

Well, that's probably the problem...

did you stick the 4 from the main ATX into the cpu power connector?

i have to make this clear the extra 4 on the ATX connector are NOT electrically compatible with the cpu power connector....this can even cause damage

Yes, I did, but I also did with the other PSU I used and it worked fine. Damn, I hope it didn't cause damage.

With this board layout it was actually physically possible to reach that far with the wrong 4 pins. Never would have happened with most gigabyte or asus boards

Well the CPU connector is so close to the ATX power connector...very misleading. I'll try using the actual CPU connector when I get a chance. Fingers crossed that there's no damage already done from having the wrong 4-pin connector plugged in.

check the colors. i bet on the other psu the colors for the 4 pins are black and yellow...(black is ground/common and yellow is +12).

what you did just fed it +12(yellow) +5(red) and +3(orange) ALL at once....and even fed power where a ground should be.....but since it shut off i think the board detected it(i hope)....

Those damn people who come up with the standards should make it so it does NOT fit, i mean you can fit a 8 pin cpu cable into a 8 pin PCI-E slot too(but it will not go the other way....)....and bad things happen....

Okay, so I swapped connectors and tried booting (without a monitor--it's 1AM, I'll try with a monitor tomorrow). It started up fine, but it seemed like the CPU fan was being loud. This does not seem like a good sign.

maybe you are just noticing how loud a cpu fan is(or speed control is off)...or maybe the old psu was loud and this one is quieter.....Fingers crossed...

Okay, the PC seems to be booting fine, but I need to re-install Windows of course. I've run into a problem while trying to do this: the PC won't recognize my keyboard. I've tried both USB and serial keyboards, nothing will work. What's going on?!

do you still have a PS2(round plug-purple most times) keyboard? try that and see if you can check for a legacy usb/usb keyboard option...also try different usb ports....

if not try this....

Look around on the board for a jumper to clear the cmos(under the south bridge and to the right a bit looks yellow in picutres).....so unlug the power supply(or just switch it off) hit power to drain any caps on the board and in the psu....now now the jumper from its current position. I think its on 2-3 so move it to 1-2 for about 5-10 seconds....then move it back and turn the power back on....this will just make sure all settings are back to the factory defaults(you will have to reset the clock and anything else you setup in the bios) for the board.....sometimes USB keyboard support goes off.....

Let me know if that works....

Oh, I meant I tried a PS2 keyboard, not serial.

Anyways, I will try resetting the CMOS. That was my first guess as well.