arduino micro not recognized anymore

Hi all,

I was working on a project with the Arduino micro r3 and everything was fine until i tried to hook up the arduino to my PC. Windows says that it doesnt recognize the device anymore and when I tried it on my macbook nothing happens at all.

I powered the micro from 12V(succesfully-led popped on etc) shortly which might have something to do with it? Although I checked and saw that 12V was fine before actually powering it with it.

What can I do???