I am having the same trouble with medialab (not RT) not advancing once a video clip has come to an end. I am using the "sample video" that comes installed with windows 7 and it plays fine, in full screen mode, but when it comes to the end I am left with a black rectangle in the middle of the medialab screen and no continue button. I have another slide that is in the questionnaire file, but it will not come up. I would appreciate help with this issue as I am trying to decide whether to buy medialab for my lab. Thank you.