keyboard not working in X
 

i could change boot menu by keyboard, but after it goes into X, keyboard doesn't work anymore, unplug ( Ps2) and plug in again cause those three small lights flashing once ( num lock caps lock scroll lock ) so i think the keyboard isn't dead and I confirmed that with a second keyboard.
what went wrong in my system ? ( fedora core 2, 2.4.22-1.2115ntpl)
thanks