I have a PC that is a couple of years old and has never given me any trouble. But it recently started having a rhythmic interference with any audio playback. Mostly it sounds like a static click, other times it sounds like a distortion of voice, but at all times its a steady rhythm. I have unplugged everything and let it sit. I have confirmed my connections are correct and solid. I have disabled everything that I can from the manager. And I still have the same problem. I am running a Pentium I7 with Windows Vista and Realtek HD integrated audio. On a side note, I have set up a dual boot with this system and on the Linux side, I get a bit of distortion at first and then it goes away.
The description makes me think its electrical noise. Have you recently added any new equipment or parts to the PC. Even something as simple as a compact florecent bulb in a lamp plugged into the same surge protector could cause this. Just for testing unplug all extra peripherals from the computer and try plugging the power wire straight to the wall.
Thank you, but I have not added anything new. And I already unplugged everything extra. I even removed the battery backup and plugged directly into the wall outlet. I pulled the desk away from the wall and spread the electrical components as far away from each other as I could. Same rhythmic distortion.