My son uses an older Dell, and the left/right arrow keys weren't working, so he disconnected the keyboard and connected an old Packard Bell keyboard.  That didn't work, so he reconnected the Dell keyboard which now doesn't work at all.  I've CHECKED the connections, and they are fine.  To add to the problem, the computer runs on Windows XP and requires a password before going beyond the initial screen.  (a password that can't be TYPED in because the keyboard won't work)  Anybody know what I should try next?Did he disconnect the Keyboards when the computer was TURNED on?

You may be able to use a USB Keyboard or PS/2 to USB converter.He says that it was turned off, but I wasn't there and really am not SURE.  

"PS/2 to USB converter"  What does this mean?

Thanks.try taking the keyboard apart and seeing if there is anything STUCK or in the way of the usage of itI believe you have got those short cables that convert PS/2 to USB. Quote

I believe you have got those short cables that convert PS/2 to USB.

Thanks, I'll try that.