[Hampshire] lost keyboard action

I was trying to mark a block of emails as spam. It started out fine and
then hung. Eventually I shut the computer down and restarted it.

I had lost almost all keyboard function. Only the up and down arrows still
work, and that rather slowly.

It is a software problem, not a hardware one. I am typing this on the same
keyboard at the same computer with the help of a live CD.

I am running Lenny.

Anyone got any ideas that might save me a reinstall??

TIA
Lisi