Note to testers-
Some Roms take a looong time to start, be patient. Just because nothing happens for 5 minutes doesn't mean it has crashed. (If the power light goes off, it HAS crashed!)
Sometimes if you are stuck on a blank screen, it may be waiting for keypress.
Some games crash randomly, so you might get as far as the intro screen first time, and you might get as far as in-game play on second try.