Put the romset (sfiii3) in the roms folder. Put the CHD file in a folder called sfiii3 and put that folder in the roms folder. It's isn't any more complicated than that. Trust me, me and Robert were on IRC for a good while trying to get this to work for me, and NOTHING! Only a few reasons why it does not work. Reason one, You do not have the corrects roms or CHD. Reason two, You are not setting it properly (I be dammed why people cannot do simple things) Reason three, Files in the mame dir are corrupt, Do a fresh install of mame (Delete the old mame dir and start again)