I have Kega Fusion 3.64 installed on my system. Outside of GameEx, Fusion will run my Genesis, Master System, & Sega CD files with no problem. Inside of GameEx is where I'm having problems. I have 3 instances of Fusion setup - one for each system. The run command for each looks like this... Master System - Fusion.exe -sms -fullscreen "[ROMPATH]\[ROMFILE]" Genesis - Fusion.exe -gen -fullscreen "[ROMPATH]\[ROMFILE]" Sega CD - Fusion.exe -scd -fullscreen "[ROMPATH]\[ROMFILE]" In GameEx, I can run Genesis games with no problem. But Master System & Sega CD games fail every time. No error message is given. When a game is selected to run, the screen will go black as if it's going to launch, but drops back to the game selection screen. GameEx has no problem recognizing that my ROMs are present as it properly lists them all and their artwork. Not sure what my next troubleshooting step is. Any suggestions?