Resolved not able to type in programs

I got a used WIN XP Pro comp for a man who was still using 2000. Fresh install of XP with SP3 and updates. Worked fine for a month until yesterday. Didn't download anything new yesterday. Uses Comodo free firewall and Avira. Yesterday he couldn't type anything anywhere. Receives emails in OE, can open a new email to send but can't type in it. Opens browsers but can't type in search or url line. Had him open start-run, but couldn't type entries.

Rebooted many times but won't go to safemode with F8.

He ran Spybot, Malwarebytes, scan with Avira. Nothing found. Emailed him the link to TM Housecall and he could click on it and run that. No threats found.

Had him sys restore to two weeks ago with no change. Undid restore point.

Any suggestions? thank you.

 

Amazing. The keyboard was dead. I was in such a hurry with a couple of other household issues at the time that the obvious never crossed my mind! thanks so much.