Sound issues when connected to VATSIM

Hi,I am having a strange sound problem when I use SB3 and VATSIM with FS9.1what happens is the controllers all sound as if they are keying their mic constantly, like in one of those comedy films.if I press the Q key in FS, then I can hear them as normal, with no problems,but as soon as I press the Q key again, they all sound as if they are pressing their transmit on and off again, and all I get is broken transmissions.they have confirmed that I am coming through to them clear and un-broken,I have un-installed my sound card drivers, and re-installed them again, all my other drivers are current.I have also re-installed Win Media Player 10, as I heard that this can sometimes cause some sound niggles.I have posted this in the SB forums, but thought I would post it here too in case anyone has had this same thing, or knows what it might be.Thanks,