Sound and video clips not working????

My MBP 2010 all of a sudden will not play small video clips...runs for 10+ seconds and stops...like no band width. Also, for the short period it runs there is no sound from the video. Everything else appears as normal. This applies to both U tube and news release videos??

I looked at sound in System Preferences and appears appropriately turned on.

Any ideas...also did a re-start.

Thanks...Tom R

 

Bump