So a couple of things could cause videos not to play. Please check the following.

1. Are you using a VPN or Proxy, if so shut it down. We have security measures in place that will prevent you from watching the videos if accessed by one of these methods.
2. Are you using FireFox or Chrome the most recent update? If not download one of them and or update your current browser.
3. Is your flash and java up to date. If not update those as well.
4. Are you using Safari or Internet Explorer or some other weird browser. If so please refer to #2.