If you notice that when you double click a video file (avi/mpeg), being Windows Media Player your default video player, and nothing happens, no window opens, no video or sound shows. Then you are suffering of what I suffered for some time now. Check your processes, to see if wmplayer.exe is listed. Try another player, and it won't happen with them. It even works well from to time to time. You should disable the monitor (AMON) and try again. If the file NOW opens inmediately, then you know the reason of the stall. It's AMON. I solved it by editing its extensions, I went ahead and pressed on the Default button.