I don't think it's Norton. Thanks for trying to help, but with or without Norton, the screen flutters, then does nothing when I attempt to open Windows Media Player. I tried to download Media Player again and kept getting the response that the version I am trying to download is not compatible with my system. I was certain it was the Windows 7 version, but tried other versions as well and continued to get the same answer. After a couple hours of frustration, I downloaded another freebie (seems to be called DirectX), which does allow me to view DVDs, although it's a bit more cumbersome. It will remain a mystery.