We are setting up an experiment in which movie clips will be presented. We made a test run a couple of weeks ago on one of the lab computers, and the movies appeared fine. But yesterday after we loaded the experiment file on all other computers, we started having trouble with the videos. The visual field was not full-screen, and its position was off. Yet this problem only occurred to some of the computers, not all of them. We used the standard movie parameter that has been traditionally used in our lab --(w1024, *1) for the first clip, (w1024, *2) for the second, and so on. With rebooting, the problem was solved on one of the computers, but not the others. Today we gave it another try, and I also changed the parameter to (w-1), but still couldn't get the screen size right. And reboot doesn't help either today. I don't understand, how come the same experiemnt file worked fine on some of the computers but not the others?