Did you turn the sound 'off' under the shirt button?
I forgot I had turned part of the sound off and couldn't figure out why I couldn't find MousseDude during the MuleBall.......a lot of his 'hints' were ambient sounds, LOL.
I have had this problem with VMK off and on. It is really bizarre. My one DD will log in and have no sound. Then the other DD will log in, on the same computer and have sound. Does not make any sense.