If you see a blank screen, please make sure you have pressed the play button for your video and wait a minute or two. If you still cannot play the video, then your issue may be due to the following:
Low Memory
If your computer has less than the minimum 512 MB of memory, or you are running many applications at the same time, please close other applications before playing a video.
Low Bandwidth
It is required that you have either a Cable or DSL modem providing at least 750 kbps download speed. Contact your internet provider if you suspect you are getting less than this speed.