@eliaspr2309 NEOGEO is an Arcade, and Arcade has a peculiarity: you need to check the ROMSET (the "version" of the ROM). Example: MAME 2003 ROMS work with MAME 2003 core, MAME 2010 ROMS work with MAME 2010 core. The vast majority of games exist in both versions, and even other versions, but you need to have your ROMSET anyway version that the core you are using.
The NEOGEO emulator has evolved a lot and is requiring another ROMSET, as MAME, as it has more than one version, sometimes changing the core solves your problem.
About ROMSET, here is the list of used ROMSETs:
The ideal is to convert your ROMSET with programs like ROMULUS or CLMAMEPRO:
Some users find it easier to download complete ROM packages from the internet, in the desired ROMSET, but it is prohibited to request or share any kind of copyrighted material on the forum, so please do not request.
About BIOS, yes, you need the correct BIOS, in the Emulationstation menu there is a BIOS checker, use it to find out which BIOS you need, and where they should be placed. BIOS is also copyrighted, so you need to do this yourself. Without BIOS neogeo will not work.