I'm having difficulty with playing the class videos on my Surface tablet - they used to work properly, but now they don't. When I click to the next slide to watch the video, I get audio, but no visual [sits at the opening part of the video - I can see that]. If I click the start button to play the video, it starts, but runs in competition with the one already started. They work on my desktop PC but I'm at a loss as to what has happened on the tablet PC. Any ideas? I guess it's a problem from my end but I have no clue where to begin.