In BIOS I turned off the USB ports (install problems with XP SP1). However, the mainbord doesn't come with ps/2 (nor floppy drive), so I can't do anything with the machine.
I have tried to reset the BIOS by unplugging the power cable, removing the battery and wait for over an hour, but still the USB keyboard won't work. I have also tried the option: remove power cable, remove the BIOS Setup Configuration Jumper, power on, power off, put jumper back and power on. No working keyboard (machine starts normally though).