Because we can't see what you said, so we have to try it
1. It's very simple, just reinstall the entire folder. Remember to check when reinstalling. Poison
2. Just take a look at the emulator you downloaded and how to use it online. I used NesterJ, which is the one that can play Mario. When you first log in, you can see the ROM in it. Content, but once selected, you cannot re-select the game, and there is no other way. If you want to play, you can only re-enter, but it is not easy to make it.
3. Just like the friend above said Yes, please format it.
4. I will give you a website. There are many simulators on it. They are very easy to use and absolutely good. If it doesn’t work, try it.
gba.com/thread-17115684- 1-1.html
That’s all I know, I hope it helps you!