unclerichard,
Welcome to the forum. I believe what you're seeing is "cannot open file delete". Does the "dead screen" you come to look like the one below?

If it does, what you're seeing is the normal behavior for safe boot. You will be at a shell prompt, in single user mode, and the only user is root. Again, if that's what you're seeing, the proper way to turn the machine off is to type in the command
halt. If you want to reboot, type in
reboot.