Can you tell exactly what you plugged into what before the first monitor went wrong? You post is very confusing.
Things you can plugin:
- a new graphic card in the motherboard
- a monitor cable in an HDMI/DP/DVI/VGA-port
- a power cable (PC or monitor) in the 220V
And how was the first monitor connected to the computer?
I told my little brother I would set up a second monitor for him just like I had, we have the same type of monitor and I thought it was an easy job and I could make his day but boy I was wrong. I get the second monitor and I plug in the cord into the gpu, and the next thing I know, before I even plug in the second monitor, the first monitor starts to have a green static and very scary looking display. I tried to turn the computer on and off and unplug everything but nothing was working. Once he pressed space bar to sign in, it brought him to a black screen that said,"out of range" in a blue box bouncing around the screen. I have basically this is a fault of the computer, it is fairly older and has been needed to be factory reset multiple times and I would be devestated to see my brother have to restart everything he has worked on by getting it reset. Not even sure how it will reset because you can't log in. Things to note now reading over it after typing all of that is that I forgot I hadn't even plugged anything in to the gpu and I was super confused why it wasn't working because of it.

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