Full screen on laptop doesnt work?

When I go on to a website like youtube or megavideo or any other website that has a full screen option, it neverworks. I get a black screen but you can still hear the actual video, it just doesnt show up, it will let me pres ESC to go back to the normal screen, but it has been doing this for quite sometime and it's really annoying. BTW it is not my webrowser, i use mozilla/chrome and ive tried it on IE and it doesnt work on any.