Com/USB Connection to Ramps stopped working (no replies)

Hello Guys
I have a Prusa with Ramp's 1.4, loaded with latest marlin firmware and using Cura , sometimes pronterface to run print jobs.
I have been printing with no connection problems for months now. The printer has had no changes and today I could not communicate with it from the computer.
I tried with Cura and it said "Error: No more baudrates to test, and no s... " literally says that".
Then I tried connecting with Pronterface and it sits there, will not connect
I also tried just talking to the arduino board with Arduino IDE program to re-load firmware. Same thing with Arduino " says can not comunicate with com port.
I have reset Arduino board "No change"
Powered off everything, unplug USB and restarted computer. "No change"
When looking in Windows / Control panel / Hardware / Com port it shows Arduino Mega 2650 (com12) so I know it see's and opens port when you plug it in.
I also have a smart LCD controller hooked up. It works fine and the machine will print "via" SD card slot. Just cant print "via" USB.
Anyone seen this before or have an idea what I might try or change??
Thanks in advance for any help.