Sound / Audio

[tammym02]

I bought this laptop less than a week ago.  I have sound when I play a dvd or downloaded zip video.  When I try to

play a video on you tube, there is no sound.  The model I own is Satellite P505-S8980

Any advice?  I also did notice on certain things, the speaker volume is very low, I can barely hear anything.  The you tube videos, no sound at all.