Category #2:
If the error is only a warning (i.e. key stuck), the POST should prompt:
1
WARNING
00100
Keyboard Error
1.
After a timeout period of five seconds without any intervention, the system resumes to boot.
Category #3:
If the error is serious, the POST should prompt:
00xx
The BIOS has detected a serious problem that prevents your PC from booting
Press <Enter> to view more information about error
Case 4 — Boot Process Fails and Error Message Displayed on Screen
15