to change the boot device on the NCR machines, while the splash screen is still open (before the beep) – press F8 and select boot device.

to get into SAFE MODE on the NCR machines, have the user wait until the splash screen is gone, should hear a beep, and F8 immediately – should open an OS choice menu, should see boot options menu at the bottom, press F8 again, choose SAFE MODE (or whatever…)