I have a Mac Plus 4mb that booted up fine with its system tools disk but I put in disk 1 of Dark Castle and a bomb appeared. Since then I cannot get it to boot up using the system disk that worked ok to start with. I have removed the power cord, left it overnight and still no luck. How do I reset it so it reads the system tools disk and boots up? I remember Dark Castle would boot up from scratch without a system disk - but this doesnt work either. Ay ideas please as I want to sell this machine complete with keyboard, mouse and a whole bunch of software.