#1 Do you know what all of those formats are?
.ZIP : Compressed file. Must be decompressed to use.
.7z : A stronger compression type than .ZIP. Also must be decompressed.
.SMC : The file type that SNES roms are known to be in.
.BIN : An uncompressed file that can be pretty much anything.
.SMS : A Sega Master System rom extension.
Most Genesis roms are zipped. Usually, the file in the zip is a .BIN file.
#2 DGen can not run files of the .SMC extension. You need an SNES emulator for those.
#3 DGen can not run filed of the .SMS extension.