Keyboard doesn't work...

I'm building a new rig, and everything seems fine except for one thing- the keyboard doesn't work. I've tried four different keyboards, both PS2 and USB types, but nothing works. Furthermore, through the use of optical mice, I've found that those ports are indeed working (the little optical LED lights up), it's just that any keyboard connected to them seems dead- no input can be received from them, and none of the LEDs (for caps lock and such) work. Anyone know what could be causing this problem?

did you check the bios to see if it was disabled?

I can't check the bios, because for that I need to press 'del' at startup, which I can't do.

then use the jumpers on the keyboard to reset the CMOS

Very good possibility that the keyboard port on the mobo is toast. The fact the a USB keyboard won't work is also attributable to the fact that you can't get into BIOS. I'd recommend you contact whoever you bought the board from and go for an RMA.