Okay, bit of an interesting quirk. I have a custom build computer, the built in sound card had some feedback issues on the speaks. From what I gathered, this can be typical of on-board sound cards, so thinking I was clever, I installed the SoundBlaster Live! card from my old Dell 8200 in it, installed http://kxproject.lugosoft.com/ these drivers which were supposed to work with the antiquated card on Windows 7. Boot it up, no change in the feedback, AND I now have no sound coming from either the SB Live card or the motherboard on-board. Racking my brain on this, I've uninstalled the KX drivers, and still no go on the sound from the on-board ports. When I use the test feature it shows sound is playing but nothing is coming out of the speakers but that dastardly fan noises I was attempting to get rid of by installing the SB Live in the first place.
-Phenom II 975 Black Edition
-16GB Corsair Vengence (2x8GB)
-Zotac 550 Ti Amp! Edition (NVIDIA)
-750 Watt power supply