| A | B |
| POST error code 1xx | System board or BIOS |
| POST error code 16x | CMOS, options or time not set |
| POST error code 2xx | Main memory |
| POST error code 3xx | Keyboard |
| POST error code 5xx | Color Monitor |
| POST error code 6xx | Floppy Drive |
| POST error code 17xx | Hard drive |
| POST error code 86xx | Mouse |
| If everything has been installed correctly during the assembly | one short beep will usually be heard at the completion of POST |
| POST typically provides three types of output messages | audio codes (beeps), onscreen text messages, and hexadecimal numeric codes that are sent to an I/O port address. |
| POST generally continues past non-fatal problems, but | fatal problems cause POST to halt the boot process. |
| Problems that occur during the POST are usually caused by | incorrect hardware configuration or installation. |