[Jay_83]

When you install EVOX it changes the boot sequence for the xbox. If there's no game inside the drive the first file it looks for is xboxdash.xbe. If this has been editied in any way then you'l get the green screen you're talking about.

Because you've installed EVOX it would have replaced your original xboxdash.xbe, therefore if you don't activate your chip it won't work.

Hope that answers your question