bionic363

Hi all, i went out and purchased an ATi Radeon Hd 4650 the other day to upgrade from my ATi Radeon x1300 series, popped the card in when i bought it installed all drivers from the cd and the card installed first time with no problems at all, I am running a Compaq Presario PC, with windows vista home premium 32 bit.
On my pc i am running a Creative SB X-Fi sound card, all my drivers btw are the most up to date that the websites offer for my stuff.
Anyways, after i installed the card i was testing how good my graphics looked when i put on some music to pass the time with windows media player, and the sound that comes out of my speakers now is all jittery is the best way i could describe it, it will play for a few seconds then stop and start constantly and if i open the ati catalyst control centre this seems to kill my sound completely for a while then it will come back all jittery again.
I have tried removing my sound card and going back to the onboard built in sound and getting the latest update of realtek audio drivers from windows as i had heard that this may resolve the issue b ut again this has not worked for me.
From what i have read i beleive i might be getting a conflict from the hdmi features from my new ati radeon hd 4650 but i have tried all i know to fix this and cannot do it, please please somone help this has me stumped, and like most of us i need my music :) :), Thanks in advance Andy.