Run WinIPAC and press the radio button that says "Show shifted keys". Shifted keys are key combo's that work like shift on a regular keyboard. These are so you can have more functions with less buttons. At least that's how I assume it works. Run WinIPAC in test mode and see if you can get that ESC key pressed using key combo's. I actually don't know much about it myself, but it's worth a look. If your saying it only crashes on the 2nd round then a shited key sounds less likely to be the problem. But it does sound more like a Mame issue than a GameEx issue too. But then you say it dosn't happen outside of GameEx. So it's a very strange problem indeed! There is probably no point in us speculating any further. You need to do more experimentation and try to identify exactly what situation is causing Mame to exit. Is it just one game, several games, is it at stage 2, or is it after a certain amount of time, what keys cause the exit or is it not keys at all, etc. etc. As Number 5 would say "need more input".