Your System is now locked.

[Guest]

I had to reboot my server (b/c it was convinced the printer had a paper jam).
Instead of booting, it gives me this message:

The RF-ID tag has changed.
System security - keyboard is locked.
PXE-M04: initializing network boot device using interrupt 18h....
System security - keyboard i unlocked.
176 the system has been tampered with.
Turn power to your system off and then on.
Your system is now locked.

 

[Roger Abell [MVP]]

These are pre-Windows messages.
Check your hardware manufacturer's documentation.