Arduino Mega not detected on serial ports

I am a newbie to the Arduino world. I was running the stepper motor example and monitoring “clockwise counter clockwise” on the serial monitor. When my dog ripped out the USB connection on the computer. Now the board is not being detected on any of the computers ports or the software. (tried two different computers same result). Board is still getting power just not communicating.
Just wondering if anyone has suggestions or has seen this before.

Thanks, SPG

I forgot to mention I tried several different cables and also did the Loop-Back test. All with no luck