PC monitor speakers buzzing noise

[Hatless]

My computer monitor's speakers have started making a constant buzzing sound. When I switch the connection over to my TV, the TV starts to buzz, and the monitor stops. Disabling the sound on my computer doesn't do anything, but unplugging the light-green sound cord makes it stop. Anyone have any idea what is causing the buzz?

 

[soundguruman]

There is a ground loop between your cable TV (cable internet) and your system.
Install a cable TV isolation transformer, at the point of entry into your house.
You have 2 grounds, one from the cable company and one from your house wiring.
You need to isolate one of the grounds, and the buzz will stop.