tonight i had a fight with punkbuster. i'm running vista x64 and i just built this computer last week.
on this fresh install of 2142, i deleted all of the movie files but had the alt-tab problem. everything played fine for the past week(punkbuster had not been updated but it hadn't seemed ot care). today, i installed the alt-tab movie patch and punkbuster pitched a fit so i had to delete it. trying differrent compatability modes didn't help at all. it was definately the alt-tab fix because that's all that had changed.