Repeating keys problem (again)

I have a Dell Precision M90 that is a few years old now.  Recently I have begun to have problems with repeating keys.  It seems like any key (including enter,and delete) or combination (such as cntl-V) can randomly repeat.  I think it is consistently 12 repeats, but I am not certain.  Curiously, this occurs with any application, and with the laptop keyboard, an external keyboard plugged into a USB port of the port extender, or a wireless (Logitech LX710) keyboard plugged into a USB port of the port extender.  In addition, the Windows function key seems to randomly toggle on, so that depressing letter keys bring up the corresponding Windows functions until I press the Windows function key to toggle it off.

I know there are a lot of forum entries on the repeating keys problem that mostly focus on replacing the keyboard or cleaning the contacts, but this seems to be unrelated to the keyboard hardware.  Is there a driver problem, or a virus, that can account for this?

Many thanks!