I am building a computer for a friend on an Epox EP-8RDA3I.

I put on HD, diskette, graphics card etc and everything looked fine until i put on a raid card that i suspect is not working anymore.
When i put the raid card - a Promise SX4000 - in my own computer, the computer will not start; fans start, but the screen stays black.

I tried it in this computer and it was just the same; even when only PSU, GFX, CPU and the raid card was connected. I tried to switch the GFX for another one and then when i plugged the power cable to the PSU, the fans started.

Now fans start when i turn on the power button on the psu!

I removed the raid card, but still it behaved the same, but now the computer was able to start when i pressed the front power-button. When i press the front power-button again, the computer turns off, but the fans keep running.

I switched back to the previous graphics card, but no change.

And holding the front power-button even for a long time does not turn off the fans. I have checked the power options in BIOS but it seems normal to me.

What is wrong?
What can i do?
What have i not tried?

Thanks in advance
Sune

Recheck the case to MB connections. Also check for a stuck button on the case.

Pin 14 on your psu mobo plug is the power-on pin. When that pins gets pulled to ground the psu goes on. Sounds like yours is constantly grounded. The only reason I can think of for this is that the new vid card mucked up the mobo bios. I would reset the bios (aka reset cmos) and see if that fixes it and if not, flash the bios.

There are BIOS's that have a on power restore option, 1-stay off, 2-turn on, 3-last state. It could be turning itself on when ever you reconnect the power cord.

Excellent. Now I have something more specific to go for

Thanks guys.

Now I disconnected EVERYTHING from the PSU, but when I connected it to power and its own power-button is on, it turns on.

It seems that besides this and that it powers up the HD and CD drives and the CPU fan, everything seems normal. When I press the case power-button, the computer starts. When I press it again, it shuts down(exept the things mentioned)

And now it blew off! With a spark and now its dead.

Then I notice this 4-pin 12V (2x yellow, 2x black) connector which I have never used on any computer before because there wasn't one on the motherboard. But on this motherboerd there is one.

Did I blow it off by not using the 12V connector, or was something wrong with the PSU?
I have another one, should I use the 12V connector here?