Hulu/ABC/Etc Sound not working - why not?

Before upgrading to Windows 7, I would click on a hulu tv show to watch and the sound would start playing with the video without any problems. Now, with Windows 7, the sound will not play with the video. But sound still works with itunes that I tried to play immediately after the sound didn't work for hulu. The speakers are on, the computer is not muted, and sound works for other programs, but the sound won't play for the streaming video websites. why not?

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