The BIOS Boot Process

 1. The power supply sends a signal to the components in the system unit.

2. The CPU finds the ROM chips that contains BIOS.

3. The BIOS performs the POST which checks components (e.g. mouse, keyboard connectors and expansion card)

4. The results of the POST are compared with data in the CMOS chip.

5. The BIOS looks for the system files in floppy disk drive and hard disk.

6. The system files and the kernel of the OS load into RAM from hard disk.

7.    Beep codes

• A series of beep: BIOS program encounter problems
• One short beep: everything is normal
• Errors can be indicated when video screen does not function
• Interpret the beep codes by consulting main board menu

8.    POST Error messages

• Error messages are shown on display system
• Interpret error messages by consulting owner’s manual