I had this problem with my PC before, the sound would rarely work. The graphics card then died so I sent it off to get repaired and they fixed the sound, but it's not working again now. Essentially, sound isn't even registering on my computer, for instance if I try to play a song on WMP it comes up with an error message. I have a feeling it could be drivers but I can't work out how to fix them as the device manager says all my drivers are up to date. My motherboard is an ASUS M2N68-VM but I don't think it's an integrated sound card, my receipt for the pc says it's 7.1 high definition onboard sound card, which I have a feeling is Realtek? Any help is much appreciated.