MameCE is built on an earlier version of Mame and requires roms of version .36 or older to work(check previous threads on where to get them). All roms go into the program files/mamece/roms folder. However, not every game listed on Megamame will work or be recognized even if the rom is version .36. Roms over 1 MB usually don't work with some exceptions(i.e.aliens-world set 1). Just try ur luck. Hopefully, now that Tekhmaster, the creator of MameCE, has found a new job(Congrats Tekhmaster!) an update version is in the works. No word yet.