BIOS won't offer the DVD drive as a choice, if no DVD loaded.
a Windows 8.1, Windows 8, Windows 7 or Windows Vista installation disc.
Modify the boot order to force the computer to boot from a USB drive, CD or DVD drive,
the boot priority in BIOS in order to allow the computer to boot from CD/ DVD.
Move “Hard Drive” to the top of the boot order list by pressing “+” or “-”.
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If you have no CD/DVD-ROM in hand, learn how to set computer to boot from USB ...
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boot order to boot from external hard drive, but no luck, what am I missing> I am ...
(if it is ON) and follow the steps below to Boot your Windows 10 Computer from USB drive.
How to change the Boot Order on Windows 10
If you upgraded your computer to Windows 10 or to Windows 8 and the drive was working before, but is no longer working correctly, you can save time by ...