To select the boot device from the startup, you should press and hold the ‘Shift’ key for a couple of seconds. In the ‘Start’ menu, you will have to click on the ‘Restart’ option. Doing so will get you the boot options menu where you need to choose an option states ‘Use a device’. After that, you will have to select the bootable device you would like to boot from. It can be a DVD ROM, USB drive, or network adapter that you can use for booting your operating system.