There are two very simple ways to boot your PC to Xtra-PC:

1.  Use the boot key to start Xtra-PC:
Turn off your PC.  Insert the Xtra-PC stick into a USB slot.  Turn your PC on and hold the boot key on your PC for 1-2 seconds (most manufacturers use F12, F11, F10, F9, F1 or ESC).  When the boot menu is displayed select USB HDD (or something similar).

2.  Set your PC to boot to USB:
Turn off your PC.    Turn your PC on and hold the setup key on your PC (most manufacturers use F1, F2, ESC, F9, F10.  It's usually displayed on your screen when the screen first starts.).  When the set up menu is displayed, look for the boot menu.  Change the boot priority to select boot from USB as the number one priority.  Save your changes.  Now when you restart your PC it will automatically look for Xtra-PC.  This will not affect your Windows operating system.   Your PC will boot normally into Windows if Xtra-PC is not in a USB slot.