To make sure that your device is in perfect order, backup everything, do a hard reset, install only mameboy and then try it. If it still doesn't work, just restore backup. It appears that some software leaves garbage in the system and it causes mameboy to stop working. I've never personally experienced this, but some people reportedly got it to work after a hard-reset.

> I tried to download both the MAMEboyX and the MAMEboy1.3 for my Casiopeia E-125
> and I couldn't get eith of them to work. They both caused an application
> internal run error and shut down (didn't even start) What am I doing wrong? I am
> running Windows CE Version 3.0.9348. I put the entire E-125 folder into the
> program folder on the PDA and it didn't work.
>