GURU WANTED--FAST!

I'm having a problem with my computer. Actually, my speakers. One day they started ringing like a telephone. It was really weird. I thought it was maybe a poltergeist, so I turned them off. The next day they weren't ringing any more, but whenever I had anything with sound, the volume was LOUD. I mean, blast-you-out-of-the-chair loud. I have this anti-pop-up program that destroys pop-up ads. Everytime it zaps a pop-up, it gives a little "pop" sound. A discreet "pop," kind of like a polite burp. But now, with these out-of-control speakers, it is going BLAAAP! BLAAAP! BLAAAP! And when this friend of mine sends me cute cartoon stuff set to music, it sounds like those cars kids drive around in rattling your windows with their rap music. BOOM-BIDDY-BOOM-BAH-BOOM! What to do? I tried turning the little knob on the speaker down, but it didn't change anything. I went through all this computer-troubleshooting routine, going to Control Panel, etc., etc., and turning down the volume there. That didn't do any good either. Any ideas, anybody? Is it my computer? Or do I need to junk these speakers and buy new ones? Hello out there? I CAN'T HEAR YOU!!!