Same problem here !
but when I hear there is a sound issue ( left speaker not working) I hit the IDT audio monitor from system tray and problem solves by itself. -_-' win xp I'say try older sound drivers, these from the CD given with your motherboard's box i.e.. you should experience less issues with these..
note: running DP35DP on windows 7 at the moment with these "new" drives
NEED decent UPDATE one that WORKS 100%
there is only hope & patience left! lol