2001 Nissan Xterra Passenger Side Window will not work.

My window quit working, in fact in slightly fell down and will not roll up or down. When I attempt to roll it up using the switch I hear no noice. When it first happened the window was stuck half way and it took a little effort to push it up so that it would close. I had to prop it up. I'm in the UK and will be traveling back to the states so I thought I'd pick-up the parts. What is your best guess based on this account that I should get to be on the save side.

As a side note the window showed no signs of trouble before this occured.

thanks