Troublesome Keyboard Error

My friend's laptop has a really crazy keyboard issue. Essentially, a

few keys will type two keys, one correct, another in close proximity;

always the same pairs. For example: Q types Q and `, W types W and F1,

P types P and -. Any external USB keyboard I plug in does not exhibit

this problem. It is only with the built in keyboard. At first I

thought it was a windows problem, but when I boot from CD into a

preinstalled environment or DOS the problem is still there leading me

to think it's a hardware issue. I have since replaced both the

keyboard and the motherboard, but to no avail. I'm not sure what to do

next... you'd think changing the keyboard, motherboard, and booting

from CD would show some improvement. I don't see how the memory or the

CPU could cause this, as those are the only two components I haven't

swapped out.

Much thanks for any help!