Problem with external harddrive after update

Hi!
I have a problem, yesterday i updated from Snow Leopard to Mountain lion. Ever since i did that i can't access my external hard drive through Finder.
I have a WD Passport, 500 GB.
I can see an icon in finder, but you can't click it at all, its as if it was invisible, or the living life had been dragged out of the poor thing
I can't click on it, can't see the files on it, and i can't do nothing with it.

I know the problem is not coming from my external drive, because i have tried the external drive on my friends computers, and it works fine on theirs.
My external hard drive is visible through the WD Smartware software, but i can't drag the files or anything through that software.
I come to you cult members in a time of need, and hope that my noob problem might be solvable.