Disconnect all internet ports first, disconnect the computer from the cable company or phone company.
Does the radio stop?
It may be coming from the cable company or phone company.
Your house may be too close to a radio tower.
There is this kit: http://palomar-engineers.com/rfi-kit
Open the computer audio mixer, this may be located in the lower right hand corner of your screen,
click on the speaker icon, do you see the volume control?
click on "mixer"
lower the audio levels one at a time on the mixer...
is there one mixer control that effects the radio? Or is the radio constant no matter what the volume settings?