I wish I could help you. I had the SAME problem, it was like my Q wasn't plugged in.
I reinstalled vista for some other reason, (my pvr card stopped being recognized by Media Center no matter what drivers I installed), and after I did that, I decided to try mobile device center again. I downloaded the newest version, then plugged in the Q. Low and behold, it works perfectly now.
The bottom line, on a fresh vista install, get the latest version of mobile device center before plugging in the Q.
If you can't get it to work, don't reinstall vista, it isn't worth it just for the Q. But if you were planning on it, give it a try after the reinstall...
