Thanks for ideas. I have checked thoroughly for viruses and malware and do not think this is the problem. I bought the computer from reputable non-profit computer recycling center. I have scanned it several times with various programs, even more than listed here, since a virus was my first thought.
As far as Firefox plug-ins, I don't think that is the problem because a similar problem happens in Explorer (I have 7).
Aside from Explorer, files in computer are up-to-date, including all Windows files. Do Explorer and Firefox use the same plug-ins across browsers? if so, you might be right that it is a plug-in problem. They are all updated. In reading how to uninstall Firefox it was a bit complicated, so I would rather not do it unless I have to.
I was able to watch a short streaming video from a british sports website (with Firefox) audio and video, no problems. When tried Hulu, same problem of shutdown, likewise a video on You-tube.
CD player works fine (WMP).
DVD player works fine with a music CD (WMP)
When tried to play a movie there was great video but no audio. (WMP).
So I seem to have 2 problems, the streaming video and now no sound on my DVD with a movie.
(There is a third problem, too: I accidentally disabled access to the DVD player and the drive icon is gone. I posted this under external hardware.)
I don't know enough to know if any of these problems are related.
My sense is that this computer was owned by a gamer who had a serious sound system at one time. There is a program for Cyberlink PowerDVD which I cannot access; presumably the paid key is long expired. But the WMP loads fine except for no sound with at least the movie I tried. Can't try another until i get my DVD icon restored.
My first priority is the streaming video issue, though.
Edited by Firetooth, 22 March 2010 - 02:29 PM.