I hope someone in here can help me.
A friend brought me an LG phone to try to get working for her. I don't know if someone tried to root it or flash it. But it won't boot past the logo screen with a "security error" on the screen. After a minute, it reboots and does the same thing. I attempted to hard reset it and I get "secure booting error - error code 1006"
I went to the internet to see if there was anything about this and I found quite a few answers/videos, etc. saying to download the LG Launcher to a PC, install it and so forth. I attempted to do this and I get an error saying it could not proceed because mfc100.dll was missing. I was finally able to fix that and now it says the app was unable to start correctly (0xc000007b).

It is an LG Stylo 2. When they came out they were on android 5.1.1 but I can't get into the phone. Surely it's been updated since then. I am running windows 10 on my PC.