Well, I'm not particularly worried about being electrocuted by my computer chassis. I wouldn't put up with what I imagine is really a 120Hz hum in the signal which you will have a hard time getting rid of with that ground connected. When you had your ground lifted, you should have measured the AC voltage between the prong and the outlet. Let's say that you see 3 VAC between ground and the prong that should be grounded. That's a deal killer for your video & audio signal but probably not an NJwirenut killer. So what if you clamp your ground somewhere between a signal killer and a wirenut killer??? Consider inserting a bidirectional transorb like a 1.5KE6.8CA or 2, series inverse unidirectional 1.5KE6.8A between chassis ground prong and Earth. That way, you can avoid the nuisance low voltage ground loops while still retaining 1500W of clamping ability to ground should the chassis try to elevate to a dangerous voltage. Just my 6 volts worth.
Joe
PS: The cost of a Littelfuse 1.5KE6.8CA at Digi-Key is $0.77, assuming you bought enough other goodies to satisfy their $25 minimum. I never seem to have a problem doing that.
