I have been using Win DVD 7 for quite awhile now and all of a sudden when I try to play DVDs or DVD files, the video and sound is very choppy like a frame by frame choppiness. It's so bad that it lags my system to the point that when I close the Win DVD program, I have to reboot the system. This does not happen when I use Windows media player 11 or Power DVD. But if I use Win DVD 1st and try another player it DOES happen. 