In order to Boot a Windows computer from USB Drive, you need a to get hold of a Bootable USB Drive for the version of operating system (Windows 11/10), which is installed on your computer.
If you do not have a Bootable USB Drive, it can be easily prepared by downloading Windows Media Creation Tool from Microsoft’s download site and following steps as provided in this guide: How to Create Bootable Windows Installation Drive.
Boot Windows Computer from USB Drive
The steps to Boot Windows from USB Drive depend on the reason for which you are trying to Boot the computer from USB Drive.
For example, if your computer is not starting up or booting into Windows, you can make use of a Bootable USB Drive to start the computer and repair the operating system.
If you are already logged-in to the computer, Windows operating system provides the option to Boot from USB Drive from within a running installation of Windows by using Advanced Startup options.
1. Boot from USB Drive When Not Logged-in
If your computer is not booting into Windows, you can force the computer to Boot from USB Drive by making use of a Bootable USB Drive.
1. Start the computer by pressing its Power button.
2. As the computer is starting up, it will be displaying scrolling messages. Look for “press F12 to select boot device” or similar message and note down the Key that is required to Boot from USB Drive.
If the computer is not displaying any messages, take a look at the user manual, visit the manufacturers website or try F4, F8, F10, F12, Esc or Del keys.
3. After noting down the Key, shut down the computer and insert the Bootable USB Drive into the USB Port of the computer.
4. Press the Power button to start the computer and immediately press the Specfic Key that is required to Boot the computer from USB Drive.
5. Once the Boot Menu screen appears, select the attached USB Drive and press the Enter key.

Note: The USB Device as shown in above representative image may be listed by its Name, Brand or listed as Removable Device.
6. You should now find the computer booting from attached USB Drive.
2. Boot from USB Drive When Logged-in
As mentioned above, Windows operating system provides the option to Boot from USB Drive, when you are logged-in to the computer.
1. Plug the Bootable USB Drive into the USB Port of the computer.
2. Go to Settings > System > Recovery > click on Restart Now button located next to Advanced Startup.

Windows 10: Go to Settings > Update & Security > Recovery > click on Restart now button located under “Advanced Startup” section in the right-pane.
3. On the next pop-up, select the Restart Now option.

4. When the computer restarts, select the Use a device option, which provides the option boot from USB Drive.

5. On the next screen, select the attached USB Device from the list of devices.

6. Once the USB Device is selected, you should find your computer restarting from the USB Drive.