Ubunutu Live CD wrecked my video on the installed Mint OS
 

I have Mint 17.3 installed on my computer. Worked good since it came out.

I wanted to take another quick look at Unity DE; so I ran the Ubuntu live CD. After a few minutes, I realized probably not going to do Ubuntu Unity.

I now can't get back to the installed Mint with the right video settings (so much for a "Live" CD not making changes to an installed OS).

When I start up Mint, I have to go in and enable my second monitor. When I do, everything switched over to the second monitor. It happens when I change the resolution to fit the second monitor. The whole menu in "Display" settings is different now. It doesn't change it when I put one as default.

How does a live CD change video settings and the program that controls it if you just run it, without installing it?

Thank you,
Chris.

Live cd should not mount disks automaticaly, but that does not mean that it don't interfere with hardware, basically try to unplug computer off AC for few minutes, it may help restore hardware to default.
If you want help with monitor config, there are plenty of tutorials for arandr and stuff, but still can ask here ;)

No, been asking for about a year, with no fix. Can't use any distro past 14.04. "no way no how."
Unplugged for a while, then plugged back in and it worked.

Thank you,

Chris.