|If the OP can view Youtube normally and see's his desktop etc as normal, I don't think its a resolution problem? Resolution would effect all that he see's not selective Youtube linked vids on Facebook, desktop included.|
* Have you tried checking you Hardware Acceleration settings for your flashplayer?
Right click the vid window during playback, go down to settings. A small window will open,here you can see if its checked or not? What ever its set to? click the check box. And then try to play a vid on Facebook again. If there is no change please change settings back to the way they were.
(The only thing is you should be having problems with all flashplayer required vids not just Facebook ones.)
* Also is your flash player up to date? http://helpx.adobe.com/flash-player...
* Next try a different browser to see if that fixes it?
Please reply and let us know if our help worked. Your feedback helps others. Maybe you?