BIOS files contain low-level hardware instructions required by certain systems. These files must be present for many emulated systems to function properly. Some games will not run without the correct BIOS files present.
Extract or install the official MAME emulator into a dedicated directory on your storage drive. Avoid installing it inside the Windows Program Files directory to prevent administrator permission errors. A path like C:\MAME\ or D:\Arcade\MAME\ works best. Step 2: Create the ROMs Directory full mame roms install
Are you using a ? (LaunchBox, EmulationStation, CoinOPS?) full mame roms install