When i play games like left 4 dead 1 and 2 i get random 1 second sound loop freezes...example when i shoot something i hear shoot voice like 3 times row and screen freezes I have put all graphic settings low as possible expect resolution and have turn off anti-alaising and multicore rendreing etc..This occurs in some other 3d games aswell but a little differend way..Well screen/sound FREEZES are the key word. I think problems started after my old gfx did die..8800gt and switched it for radeon 4670..I did test 9800gt as well but had same sound loop freezes :S Sometimes i can play 2 hours row without any problems after restarting computer then sometimes freezes begin right away..Very strange...Like my computer has it own mind. I have closed all possible programs and test game booster and mz ram booster etc but no effect Really...I did try some driver sweeper program to delete old card drivers but that didnt help either.. would really need help with this..
Your sound card could be going bad if it is dedicated. If it is onboard, I suggest that the CPU gets replaced and the BIOS get updated. Why? Onboard sound resides in the CPU and if it goes bad, your whole CPU must be replaced to replace the onboard sound. Reflashing the BIOS is necessary because after reflashing, the BIOS redetectes all devices installed.