overlay failed & netmeeting
 

I saw posts about problem with overlay and netmeeing and when netmeeting ois Off it works fine, but I have another question about that.

I'm using Win XP Pro, and have 4 usern on system. When I log on as me, NetMeeting starts with windows and when I try to watch divx I get error Overlay failed. Now I don't turn off NetMeeting but insted I switch user, and log on as another user. I don't log Off my self just change user. On ather account NetMeeting doesn't start and I can see movies without any problems. On that account I jest play movie for about 2 sec., then completly logOff and return to my account. Now I can watch movie on my account with no problem. NetMeeting is still runing but I stil cen see movie. Can anyone tell me why is this hapening, and how is it possible?