Updated: 08/03/2018 by Computer Hope

Boot may refer to any of the following:

1. Alternatively referred to as boot up or sometimes start up, booting is the process of powering on a computer and getting into the operating system.

What happens when a computer is booting?

During the boot process, the computer will go through multiple steps, to ensure the computer hardware works correctly and the necessary software can be loaded. When booting, the computer will perform the following tasks.

  1. Pressing the power button on the computer starts up the power supply, which subsequently provides power to the other hardware components inside the computer case.
  2. A self diagnostic is performed, also known as a POST, to check if all hardware in the computer is working properly.
  3. The BIOS checks the hard drive for the boot loader, located in the first sector of the hard drive.
  4. The boot loader looks for the operating system on the hard drive and begins loading the operating system that is found, like Windows or macOS.
  5. Hardware drivers are loaded, allowing the operating system to interact and utilize the hardware components inside the computer case.
  6. If configured in the operating system, a login screen is displayed, allowing a user to enter a username and password to log in.
  7. Any additional software programs that are configured to start with the operating system, known as startup programs, are loaded. Common startup programs include antivirus software or printer management software.

When the computer is booting, you may see a boot screen similar to the example picture below.

Computer Boot screen

In the above example, the screen is displaying the BIOS information, the type of computer, CPU, and memory for the computer and a prompt to enter BIOS setup.

Failure during boot

If the computer cannot boot, you may receive a boot failure error. This error indicates that the computer is not passing POST or a device in the computer, such as the hard drive or memory, has failed. You may also hear a beep code, to help you identify which hardware is failing during the POST.

If operating system files cannot be loaded, due to not being found or being corrupt, an error message or blue screen may show on the screen. The error message or blue screen will help identify why the operating system cannot be loaded.

You may also see a blue screen if a hardware driver is corrupted or cannot be loaded for another reason. Sometimes the operating system can continue loading even if a hardware driver cannot be loaded, however, you will likely experience problems using that hardware. Additional errors or blue screens may occur as well.

2. See the kick definition for additional information about what it means to get boot or booted from chat.

Boot code, Boot sequence, Bootstrap loader, Chat terms, Cold boot, Initialize, IPL, Reboot, Shutdown, Splash screen, Startup, Warm boot