Pat Marr is thinking along the same lines as I am on this. Could be a bad USB to keyboard cable. Worst case scenario is that the keyboard side of the USB may be in need of a visit to the repair shop.

You've tried substituting a known working USB cable. If no joy, try that known working cable on another computer with known working USB. Isolate like that so you can find out what is really going on.

Might be the computer has blown USB hardware, or possibly the power supply in that puter is going out.


--Mac