Chapter 2 · System Recovery and Advanced Maintenance
2.4BIOS/UEFI and Boot Process Awareness
What firmware is, how BIOS and UEFI start a computer, the POST test, opening BIOS settings and changing the boot order.
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Full Stack Developer · AI Engineer · Reviewed 20 Oct 2026 · 3 min read
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You press the power button and, a few seconds later, Windows appears. In between, the computer does a lot of quiet work. A small program on the motherboard wakes up first, checks the hardware, and then finds the operating system. This topic explains that program and the settings it gives you.
Role of BIOS / UEFI in Computer Startup
The first software that runs is not Windows. It is firmware. It sits on a chip on the motherboard, not on the hard drive. So it stays safe even when the power is off.
There are two common types of firmware:
| Firmware | Full name | What it looks like |
|---|---|---|
| BIOS | Basic Input/Output System | Older. A basic, text-only menu. Keyboard only. |
| UEFI | Unified Extensible Firmware Interface | Newer. A graphical menu with mouse and keyboard. Supports larger hard drives. |
Whichever one your computer has, it does three jobs at startup:
- It checks that the hardware works, like the RAM, the keyboard and the hard drive.
- It finds the boot device, such as a USB or the hard disk, and starts the operating system.
- It lets you change settings like the date, the time and the boot order.
The POST Test
The very first check is called POST. Think of it as the computer taking its own attendance before class starts.
POST looks at the most important hardware. If everything is fine, the computer goes on and loads the operating system. If something is wrong, the computer may beep, or show an error message on the screen.
Accessing BIOS and resetting to defaults
Sometimes you need to go inside BIOS/UEFI, to change a setting or fix a problem.
How to Open BIOS/UEFI Settings:
First shut the computer down. Then switch it on and press the setup key straight away. Common keys are Del, F2, F10 and Esc. The right key depends on the brand, for example HP, DELL or MSI. The BIOS or UEFI screen then appears. Figure 2.4 in the book shows one such screen, with the Boot tab open.
Resetting to Default Settings
Did you save a wrong setting? You do not have to remember what you changed. Pick "Load Setup Defaults" or "Reset to Default" inside BIOS/UEFI settings. This puts the firmware settings back to how they were.
Boot order and boot repair
A computer can start from more than one device. The boot order is the list it follows.
For example, the computer may try the USB drive first, then the hard drive. To change the order:
- Enter BIOS/UEFI settings.
- Go to the Boot tab or menu.
- Move the device you want, for example the USB, to the top of the list.
- Save changes and exit.
This matters when something goes wrong. Sometimes a computer cannot start because files are missing or there are errors. The book's fix is Startup Repair, run from a Windows recovery USB or DVD. To start from that USB, it must come first in the boot order.
Practice this topic
Short questions
1.What happens during the Power-On Self-Test (POST).2 marks
Answer
POST stands for Power-On Self-Test. It is the first thing the firmware does after the computer is turned on. POST checks the most important hardware to make sure everything is working properly. If all parts are fine, the computer continues to load the operating system. If something is wrong, it may beep or show an error message on the screen. Example: If the RAM is missing, the computer will beep continuously.
2.Why is the boot order setting important when using recovery tools from a USB drive?2 marks
Answer
Boot order means the sequence in which the computer looks for a device to load the operating system. For example, it may try the USB drive first, then the hard drive. So to start from a recovery USB, you enter BIOS/UEFI settings, go to the Boot tab or menu, move your desired device (e.g., USB) to the top of the list, and save changes and exit.
3.What is firmware?2 marks
Answer
All computers have special software built into the motherboard called firmware. It is not stored on the hard drive and does not get deleted when the computer is turned off. Firmware gives the computer basic instructions on how to start.
4.Name the two common types of firmware and write one difference between them.3 marks
Answer
The two common types of firmware are BIOS and UEFI. BIOS is older firmware software that shows a basic, text-only menu and works with the keyboard only. UEFI is a newer type of firmware software that supports a graphical menu, that uses both mouse and keyboard, and larger hard drives.
5.Write the role of BIOS/UEFI in starting the computer.3 marks
Answer
BIOS/UEFI checks if the hardware is working correctly (like RAM, keyboard, and hard drive). It finds the boot device (USB, hard disk, etc.) and starts the operating system. It allows users to change system settings like date, time, and boot order.
6.How can you open BIOS/UEFI settings?2 marks
Answer
To open this setting, you need to shut down your computer. Turn it on and immediately press a key like Del, F2, F10, or Esc (the correct key depends on the brand, like HP, DELL, and MSI). The BIOS or UEFI screen will appear.
7.List the steps to change the boot order.2 marks
Answer
Enter BIOS/UEFI settings. Go to the Boot tab or menu. Move your desired device (e.g., USB) to the top of the list. Save changes and exit.
8.How can you reset BIOS/UEFI to default settings, and what can be done if the computer cannot start due to missing files?3 marks
Answer
If the wrong settings are saved, you can restore the system to its original state by selecting "Load Setup Defaults" or "Reset to Default" inside BIOS/UEFI settings. If the computer cannot start due to missing files or errors, this can be fixed by using Startup Repair from Windows recovery USB or DVD.
Long questions
1.What is firmware? Explain the two common types of firmware, the role of BIOS/UEFI in starting the computer, and the POST test.8 marks
Answer
Cover four parts, quoting the book:
- Firmware: "All computers have special software built into the motherboard called firmware. It is not stored on the hard drive and does not get deleted when the computer is turned off. Firmware gives the computer basic instructions on how to start."
- Two types of firmware:
- "BIOS older firmware software shows a basic, text-only menu and works with the keyboard only."
- "UEFI newer type of firmware software, supports a graphical menu, that uses both mouse and keyboard, and larger hard drives."
- Full forms from the book: Basic Input/Output System (BIOS), Unified Extensible Firmware Interface (UEFI).
- Role of BIOS/UEFI in Starting the Computer:
- "Checks if the hardware is working correctly (like RAM, keyboard, and hard drive)."
- "Finds the boot device (USB, hard disk, etc.) and starts the operating system."
- "Allows users to change system settings like date, time, and boot order."
- The POST Test: "POST stands for Power-On Self-Test. It is the first thing the firmware does after the computer is turned on. POST checks the most important hardware to make sure everything is working properly. If all parts are fine, the computer continues to load the operating system. If something is wrong, it may beep or show an error message on the screen." Book example: "If the RAM is missing, the computer will beep continuously."
Aim for 200-300 words.
2.What is boot order? Explain how to open BIOS/UEFI settings, how to change the boot order, how to reset to default settings, and how a computer that cannot start can be repaired.8 marks
Answer
Cover five parts, quoting the book:
- Boot order: "Boot order means the sequence in which the computer looks for a device to load the operating system. For example, it may try the USB drive first, then the hard drive."
- How to Open BIOS/UEFI Settings: "To open this setting, you need to shut down your computer." (i) "Turn it on and immediately press a key like Del, F2, F10, or Esc (the correct key depends on the brand, like HP, DELL, and MSI)." (ii) "The BIOS or UEFI screen will appear." (Figure 2.4 shows such a screen.)
- How to Change Boot Order: "Enter BIOS/UEFI settings." "Go to the Boot tab or menu." "Move your desired device (e.g., USB) to the top of the list." "Save changes and exit."
- Resetting to Default Settings: "If the wrong settings are saved, you can restore the system to its original state by selecting "Load Setup Defaults" or "Reset to Default" inside BIOS/UEFI settings."
- Boot repair: "Sometimes the computer cannot start due to missing files or errors. This can be fixed by using Startup Repair from Windows recovery USB or DVD."
Aim for 200-300 words.