What would cause a computer to black out momentarily while watching online TV?

Have you updated your drivers recently, if not update your drivers for the computer.

Possible GPU is going bad?

The NSA.

I would think, some incompatibility between your current graphics drivers and the way the video display works on Fox and NBC. Presumably the videos on CBC and ABC are slightly different somehow. Try updating the drivers and if it still doesn’t work I would think that the graphics card is either outdated or starting to fail, and needs to be replaced with a new model.

Although in hindsight it seems that @rojo has hit it upon the proverbial nail, it seems that the problem lies with nbc and fox (whom I will no longer be visiting).

I did try updating and same problem.

They are most likely using Flash to display video. So I would also suggest upgrading your Flash plug-in if you haven’t already.

http://get.adobe.com/flashplayer/

It is possible that NBC and FOX are incompatible with your current version of Flash and your current graphics drivers. Also.. Do you happen to use Chrome as a browser? It ships with it’s own version of flash.

Thanks @johnpowell I just downloaded from your link. I’m off to see if Blacklist or Revolutions will play.

Also, am not using Chrome. I am pretty much exclusively on Firefox.

That is a problem with Windows and the integrated graphics driver. It used to happen to me. Run Windows update. It should solve the problem.

Tried Windows Updates to no avail. However, @johnpowell seems to have nailed it with the link to Adobe.
I thought I had already upgraded to 12. whatever but it seems I had not.

Thanks again, John.