High pitch whining noise, pitch changes with volume

I have recently been experiencing an issue where the speakers are making a very annoying high pitched noise that sounds like a dog whistle or something. The interesting thing is that the pitch of the noise changes in steps when I adjust the volume. Also, it only makes this noise when no other sound is playing. Help would be greatly appreciated.

Unplug the speakers from the PC and with the speakers powered on see if the sound is still there. If it is the problem is in the speakers and not the PC. If the sound goes away when the speakers are not plugged in, plug a headset into either the front panel headphone jack or the rear GREEN speaker jack and see if you hear the whine. If its not there with headphones it could be the cable that is used to connect the speakers to the PC is defective.

If its still there with headphones, the sound may still be present when other sound is playing but whatever audio is playing is just masking the high pitched whine. The first step is to make sure you have the PC vendor (or motherboard vendor's) sound driver. Non vendor sound drivers many times will not work or work correctly.