Have you got access to or tried a USB keyboard?
If you boot into dos (via a dos disk?) Can you use the keyboard properly?
edit.... If you have no luck but DO have USB on it - I have a usb>ps2 keyboard converter that I could send you.... PM me if you want it

(note I got it with a keyboard and I can't say %100 it will only work with that keyboard - but you are more than welcome to try)