Fixed, had same problem
I had the same problem and after searching, it seemed that a lot of people are having this problem. There was something wrong with the latest update to flash player and they have fixed it but they didn't release another update with the fix, they just fixed the bug. I have google chrome and IE 9 and google chrome comes with flash player but you can also download and install flash player from IE 9 so you end up with two flash players. What I did was uninstall both flash players and google chrome. Reset the computer then download and install google chrome and don't install a second flash player from Internet Explorer. Another thing causing this problem for people was using hardware acceleration for flash player and to turn this off, open up google chrome and go to any video that uses flash player and right click on the video, click on settings not and uncheck the box for use hardware acceleration and then close the browser and reopen it to make sure the changes are applied. This fixed my problem and hope it fixes yours.