front passenger window
Either the window regulator has failed, or the glass has come off the track. You will have to remove the inside door panel and inspect everything. When you attempt to lower and raise the window with that door panel off, it should be easy to tell what's amiss. If the glass just came off the track, you probably won't need any parts, but if you need a new regulator, a salvage yard will save you some bucks.
Search Pontiac Grand Prix Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Pontiac Grand Prix Experts