Sorry for the vague post. I've since fixed the issue. The latest nvidia drivers were the problem (266.58). I rolled back to 260.99 and everything works fine now. It wasn't gameex that was crashing windows, it was MAME. FYI: Windows XP SP3 Nvidia 7800GT
I updated GameEx yesterday and now when attract mode starts windows crashes. I haven't had any time to dig into it but was wondering if anyone knows anything off the top of their head. It was fine before the update.