When I say strange noises I don't mean pops or clicks. I mean voices, and music. Even when no programs are running. Happens at random times. Sometimes they sound like radio ads, sometimes music, sometimes bizarre sound effects. I've run AVG Virus Scan and Spybot S&D, and the problem persists.

How clear are the noises? Is it consistently clear, or often very distorted?

It might have nothing to do with your PC at all. It sounds like there is an electrical interference, which could mean you are picking up genuine radio signals. Try turning your pc off, but leaving your speakers on, you might still get the noise, proving it is not your PC.

I have seen stranger things. Once, at a friends house, we started to hear what sounded like air pilots communicating out of his bass amp. We soon discovered that it only happened when the chain attatched to his wallet touched the strings of the guitar.

If it is annoying you, maybe try to shift the positions of speaker cables, make sure they arent in direct contact with anything magnetic.

Hope this helps.

Huruey