The most sure-fire neogeo emulator has to be neorageX. :o
I believe it emulates the hardware
of the neogeo and the system rather than attempt to emulate each game seperately, so it works in most cases, though not for newer games for some reason. :o
If you have a winXP pc youll need neorage XP instead in order for it to run under XP. You can get the hack v0.8c
here. :L
Its not perfect in any respect, but it will run most old games, and the newest ones can be run in either nebula or kawaks, though i recommend kawaks, as i never really felt like spending the time setting up nebula. :>
You can get kawaks 1.46p
here, it can run
SVC Chaos and everything. :o
With any emulator, make sure all directories are pointed in the correct direction, though, the not detecting roms sometimes is just a bug, in this case, just keep moving the roms and redirecting the file paths until it works. :/
Also, with nebula and kawaks, you normally need the correct rom file and *.ini for the rom you wish to play, normally posted on one of a thousand-hundred-billion mexican or brazilian rom sites. :o
EDIT:
the previous poster is also right about the renaming bit:>