Not too sure what what I've done, but I guess I messed things up.

Tried to install a backup camera, and I never even got a picture.

I wired the black wire to ground, and the reverse gear signal wire to the to the red camera wire.

The yellow VGA cable to the brown hookup behind the stereo.

Powered up, but could not get a picture going. So I started messing with the settings, and turned the rear camera on.

Still no picture... Tried a couple different settings, and still nothing, double checked wires... everything looked good.

I got a little frustrated and walked away. Came back an hour later, and now when I turn the car on (AVIC-7200NEX)

You hear the system self test, then a black screen with the saying, the image maybe reversed...

From there, I can do NOTHING. The buttons don't work and the screen doesn't change (car is in neutral)

I unplugged the camera and power harness waited a few minutes, plugged the harness back in, but no change.

I left the camera unplugged and disconnected the reverse gear wire.

So the unit powers on, the buttons don't respond, and a black screen with the text "Camera image may be reversed" is shown.

help?!

Did you wire the reverse signal into the reverse wire trigger of the head unit as well, there might be a setting for positive or negative trigger as well.

Is it the OEM camera or an aftermarket one you installed?  Many OEM cameras are 6V cameras, axxess sells the ax-cam6v regulator.

This is the camera I picked up: Esky EC170-25

https://www.amazon.ca/gp/product/B00XTZUHOM/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

I'll admit I never read the instructions...

I hooked the black wire to ground, and the red wire to the reverse lead on the radio.

I never thought there would be such detrimental affect on the radio!

Either way, there was nothing I could find to restore the radio, I've only had it a little over 3 weeks, and warranty will look into it.

I'll just be without a stereo for a few weeks.

Hard lesson learned 

disconnect your battery for 5 minuets i had my screen go black like this as well before , it will make the deck reset and loose all settings happened to my 8100 nex    i wish there was a save settings feature on this unit.

the setting that made this happen is the reverse ground option on my deck.  if you can get it to reset you will be fine.

That's not how you hook it up.  The reverse signal of the radio is supposed to go to the reverse signal output of your gearshift or you can tap the 12v from your reverse light bulbs. 

You can also tap 12v ground and power from your reverse light bulbs for power to the camera(red and black wire). 

The only wire that should go from the camera to the head unit is the yellow rca cable.