I can't remember when the movies play on those, since I had to disable mine, but there's always a chance that's what the problem is. At the least, it wouldn't hurt to rule it out.
In the nwn.ini file, the three lines to try playing with are:
SafeMovie=0
Disable Intro Movies=1
Disable Movies=1
That's my settings under win7 for the movies, try disabling them and see if that makes a difference, or if running them in the SafeMovie mode does.