I'm stumped! My wife uses IE9 and her machine and has a problem that I can't solve having spent several hours trying.
Her friends send her links to their YouTube videos but they won't play --- hang up after starting for a few seconds. The same video will play fine on two other machines that are set up the same (I think).
I've checked through the internet options, plus googleing for info, and have the right video players available for YouTube.