[Elecraft] K3s won't connect to PC

[KE8G]

Hi All,
Strange thing!  I was working a DX station and my PC locked up, and kept
sending my call sign.  The only way to stop the RF was to turn the rig
off.  I let it sit for a minute or two, then turned it back on.  The LCD
screen flashed a ERR PTT.  I disconnected the WinKeyer and plugged it back
in and was able to work the station with the paddles, rather than N1MM+

Now, I can't get the K3s to connect to the PC (Win7 Pro 64bit).  It shows
as a unrecognized USB device in the Device Manager.

I have shut everything down, PC, K3s, WinKeyer and removed power from all
and let it sit for awhile.  The PC starts fine, the K3s starts up fine (no
ERR messages) and works well, the Winkeyer works fine.

I know the K3s was communicating with the PC earlier, as I was using the K3
utility to set roofing filters I just installed in the sub receiver.

Any suggestions on where to begin looking would be a great help.

Thanks in advance.
73 de Jim - KE8G