[header] How to boot from an external hard drive [title] Swipe in from the right side of your screen and tap on " settings. [substeps] If using a mouse, point to the lower right corner of your screen, move the mouse pointer upward, then click on " settings. " [title] Tap or click on " power, " then select " restart. 
[title] Press and hold down the " shift " key as your computer restarts. [title] Tap or click on " troubleshoot " when windows 8 prompts you to choose an option.