I searched all over for a solution to my moment not mounting to windows and nothing worked until I just stumbled upon what worked: USE THE CABLE THAT CAME WITH THE MOMENT! Sounds sarcastic right? No but really, I happen to also have a longer usb cable that I used to charge my phone and have it stretch from the socket to my end table. It charges fine but wont mount my phone when plugged in to windows. I just so happened to use the USB cable that came with the phone and BOOM it mounts every time! Hope this works for some people.
