Dell Latitude keyboard not responding

[jimmoo]

I have a Dell Latitude CPt.

The integral keyboard will not respond at all.
Touch pad is fine.

An external keyboard fitted to ps2 port works fine.

The laptop has had a new hard drive fitted with a clean install of xp pro.
No conflicts or evident software issues.
There does not appear to be any bios settings which would affect integral keyboard.

Thanks for any help