Moving files from reprogrammed card to new card

[A Former User]

I own a Retropie which originally came with a preprogrammed card I bought online. The Retropie got messed up when I tried to add more games to it, so I'm going to try and fix it over the next month or so. I'm going to move all the games, and the bios to a flashdrive, then I will wipe the original SD card clean, rewrite the Raspberry Pi system to it, and then put everything back. In terms of the files I need, should I just move the bios and the games, or are there other files I need? Also, just to address this, I bought a preprogrammed card because I couldn't find the bios online anywhere, because it's taboo to say it, and though I was able to program the Pi by myself, after turning it on and off a few times, it would boot to a sort of error screen with the Retropie logo written in text. I don't know why it did that or what the error was for.