Problem with A7N8X-X onboard sound.

I have an Asus A7N8X-X motherboard which is an nForce2 chipset. The onboard audio was fine for the most part up intill just recently. For some reason I'm now getting a fairly quiet high pitch humming sound constantly and its annoying the heck outa me. When ever a sound is played the humming goes away for a few seconds but then returns. So if I'm playing music or a game or something I don't hear it because sounds are constantly being played. Theres only one driver I know of for this audio piece so I can't try a different driver. Also I don't see why it would be a driver issue since it had been working fine up intill just recently. I maybe wrong but I think I may have started hearing the humming just after the power in the room I'm in flickered causing the computer to reboot. Anyone have any suggestions as to what the problem might be?

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Canada
Asus A7N8X-X, Athelon XP 2500+ Barton,
Samsung 1024mb DDR400, MSI GeforceFX5900 XT.
Aquamark=<b>34702</b>

I had a very similar problem with my guitar amp, solved by grounding it. I'm not an electrician, but maybe the power outage somehow messed up the grounding in the pwersupply to the subwoofer?