My arduino uno not recognize on pc


I'm using arduino for 6 months and all is good. But today I use a driver shield for motor with 12V of external power. When i connect the arduino to my PC. My computer shutdown instantly and the arduino still with the led ON , TX and L but my computer don't want to recognize him. Have I burned my arduino uno or is it just a pc problem ?

When i plug it to my pc those leds light on but my PC don't recognize the arduino.

I wait for your response ^^, thanks

A lot of the driver shields have a JUMPER or TRACK that must be cut to allow an external PSU to be used.

Did you set the jumper or cut the track if yours has one of these ?