I'd suggest using subpage logic to accomplish this.

Draw a Sub page and drop it on to all pages in the project. I'd suggest having the logic in place on the first so that when you copy and paste on to other pages you don't have to go back and waste time adding the logic.

How you activate this subpage depends on the device. If you have a display or projector that will provide "ready" or "on line" status you can base the subpage being high on this being false.

Or you can use the built in timing logic macro in Systembuilder and have the subpage triggered by that logic.

Alternatively, if you have logic macros that track device ready, you can have the subpage linked to that logic.

This same programming logic can be used to launch "do you want to turn system off" sub page, if that's how you want the client to turn the system off.

Alan