If it's not the Mysterons you could try creating a new profile in ET (just to eliminate the possibility that there's a bad setting in there causing the audio/frame glitch).
Also, did you use a driver removal program after uninstalling the drivers to make sure no remnants were left? I haven't had to use one of these for a while so unfortunately can't recommend any...
Oh, and if you have a sound-card (as opposed to built-in motherboard audio) you could check in device manager to ensure that it isn't sharing an IRQ with the graphics card (if it is, change the pci slot the sound-card is in).
You could try re-installing DirectX too.
I hope something there helps, was just shooting out ideas that came straight to mind
Good luck!