If you have no errors in device manager delete all USB devices and let Windows reinstall them when restarting the computer. If this does not work then fit a USB keyboard and see if it works in the BIOS. If it does then the USB ports are OK and you should try the Microsoft web pagehttp://support.microsoft.com/kb/925196
Chose the "lets fix it myself section"
If the USB keyboard does not work in the BIOS then the USB ports are faulty and a possible work around would be to fit a PCMCIA USB port.