Probably not much you can do if the save state and save game files got corrupted.
Also, you shouldn't use save states and actual save game files together. Use one or the other, combining can cause corruption.
yes
Then you have something setup wrong in LB.
Do other systems games work through LB with Retroarch ?
Double check your platform name you imported the games to. The platform you imported games to needs to match the name in the associated platforms list of the emulator.
In your screenshots you have the bsnes_2014 core selected.
I would advise using the snes9x core, the one without a year in its name.
Also double check that the platform you have your SNES games imported to is the same as in the associated platforms list.
I just saw your post on the sub reddit and it appears you are looking for a pre built system download. We do not condone or support those here.
Locking thread.
I don't know if this will work still but here is a portable zip of my Kat5200 setup I made a while back. It should just be a simple extract and go but I have not tested it in a long while, I still had this on my old PC.
LB is just a frontend.
Kat5200-Portable.7z
Sounds like you are using Retroarch and the core selected is the 2024 core which is a game. You would need to change the core to the correct one for Atari 800 but it will take some extra steps to get working.
https://docs.libretro.com/library/atari800/
My advice would be to use the stand alone emulator Kat5200, it's a great emulator and is the easiest 5200/800 emulator to get setup: http://jillybunch.com/kat5200/