Booting your computer from an external hard drive is a notion that may seem ludicrous to many individuals. For many, the idea of booting an operating system (OS) is a task designed for the computer’s main hard drive; booting from anything else is asking for trouble. However, due to the increased size of external hard drives, an OS can easily be booted if you have a mirror image of your computer’s main hard drive. This process is essential if the main drive has crashed, and you must continue using your computer.
1. Reboot your computer. Press the “F2” button when your system information is displayed. After a few seconds, you will be taken to your computer’s Basic Input/Output System (BIOS) menu.
2. Press the arrow keys on your computer. Navigate to a section entitled “Startup,” or its equivalent. You will see the priority order of what device boots first. Normally, the computer’s hard drive is first in the list. You will need to change this default to boot via an external hard drive.
3. Highlight the item that refers to the “USB device.” Press the “+” key on your keyboard to raise the priority of the USB device. Keep pressing the key until the USB device is the first on the priority list. Insert your external USB hard drive. Click the “Esc” key. Select “Save and Exit with Changes.” Your computer will now reboot, allowing you to boot your backed up operating system via your USB external hard drive.