Tracking down interference like this can be a challenge. To do it right takes experience and the right tools. It's easy to get frustrated, and it's also difficult for us to help you out remotely since this can be complex stuff to try and explain online.
So I think this is what has been covered:
Pro 197 scanner with stock antenna.
You get 'full bars" interference on VHF.
You've shut off all the circuit breakers in your home and the noise is still there.
No clear offender that may be causing this.
When you shut off the circuit breakers in your home, was there any networking or cable TV stuff running on a UPS?
How close is your home to your neighbors? Entirely possible they have something that is causing the noise.
Solar panels, LED lights, lots of consumer electronics can cause this. Your home does not have an invisible forcefield that will protect you from noise coming from a neighbors home.
Cable TV systems can leak, but that tends to result in interference on specific slices of the bands, not wideband-across the spectrum stuff.
Didn't you have an external antenna installed on your home? Did you try hooking this scanner up to that antenna?