Passport is line of portable USB external hard drives developed and marketed by Western Digital. You can use a Passport to back up your data or carry your data around. You can also use your Passport external hard drive to boot your computer. By default, your computer is programmed to boot from its internal hard drive. As an administrator, you can boot from a USB device from the BIOS menu.
Connect your Western Digital Passport external hard drive into one of the open USB ports on your computer.
Restart your computer.
Press the appropriate key during start-up to access your BIOS menu. Note that PC and BIOS manufacturers may use a different key or combination of keys in order to enter the system BIOS.
Use the arrow key to highlight the option "Boot from USB device." Press the "Enter" key. If your computer uses the "Setup" menu instead of "Boot Menu," choose "Settings." Next, choose "Boot Order." Use your arrow keys to change the boot order until the USB drive appears first.
Press the key as prompted at the bottom of the BIOS menu to save and exit. This will restart your computer and force it to boot from your Western Digital Passport external hard drive.
Your Passport drive must be bootable, otherwise the computer will return an error if you attempt to boot from it.