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In order to change the boot sequence press the "F12" key at the boot, as soon as you see the Lenovo Logo comes up ans select the device you want to select to boot from.
In case the computer does not shows the device you want to boot from in the "Boot Menu", we'll need to change the "Boot Mode" in the BIOS Setup Utility from "UEFI" to "Legacy Support", in this case I need you to download the "User Guide" for your Lenovo at this link: http://cdn.cnetcontent.com/e7/e1/e7e17900-6c15-4073-b757-140d2b919f74.pdf
To enter the "BIOS Setup Utility" Locate the "Novo Button" (see page 7 of the User Guide) and press it with your computer OFF; now check the "Boot Mode" settings and change it to "Legacy Support", if the device still does not appears in the "Boot Device List" replace it with a new device or a new medium.
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