I can’t hear sound in game.
If you are using Skype or other communication software, you might want to change some settings in the windows sound system.
Also, check if you are using ASiO4ALL sound driver, softwares that use that like Fruit Loops, when it is being used, it eliminate most of the other programs sound, or more like, lock the sound to the main software only till you close it.
I don’t know of other drivers that could cause that tho.