Skyrim Audio Problems
I recently upgraded from a Radeon HD 4350 to a GTX 550 TI and whenever a load is placed on the GPU, such as running games or opening the Nvidia manager, the audio will crackle and pop. This makes Skyrim quite unplayable as I can't hear anything over the static. My drivers are up to date and I already tried setting the audio to 16 bit/41k.
Do you have a digital audio out? If so, there's a chance the interference on your analog outs will not have also infected the digital out. (but it depends where the corruption is happening.)
Other possibilities: try a soundcard vs onboard audio (or the reverse); upgrade your power supply; try another motherboard.
All these are guesses, I can't guarantee that any would work, so hopefully you can find a way to experiment without committing to a purchase.