Hope someone can help...

I was trying to use a 20-pin ATX PSU with this board, the manual says that it will work with either a 20- or 24-pin PSU, however, I can't get a 20-pin to work with it. 24-pin works fine. And the 20-pin has tested fine on another board.

When trying with the 20-pin, it sounds like the computer is starting up, I can see the CPU fan coming on, and can hear the hard drive spinning up, but the monitor stays in standby (power button goes red, like when it would go when going into power-saving mode; "no signal" is different behaviour). There is no beep, which is normally heard when BIOS startup is successful and it begins loading the OS.

Using on-board graphics, and just one SATA drive (HDD). One 2GB stick of DDR2 in use. Like I said, a 24-pin works fine with the G31M-GS, and the 20-pin works fine in another PC (GX260).

BIOS: G31M-GS P1.40

Anyone know what might be up?