Hello I have been trying to boot off of a usb removable DVD drive that has a norton rescue disc DVD in it and can't get it to boot off the cd. I have been trying different keys like function keys and also delete and escape when the laptop boots off and no good. I have a Dell Inspiron 15 7000 Model number 7537.
-Thanks for your time.
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Please tap on the F12 key at system start up for the one time boot menu and select the external DVD drive to boot from it. If you are still having issues, I would recommend you to change the boot priority order on the BIOS (F2 at system start up) and select the external DVD drive as the first boot device, save settings and restart the computer to boot from it.
In order to boot a DVD, secure boot must be turned off and legacy boot must be enabled (F2 at powerup to change the settings).
Be VERY careful to ensure the disc you have is compatible with your system and UEFI -- if it's not, you may wind up with a corrupted hard drive. You will need to reverse the changes you make before booting WIndows again -- if you leave the system in legacy mode, Windows will not load.
My Inspiron 7537 boots to DVD disks fine when both UEFI boot only and secure boot is enabled - provided you are using a UEFI bootable CD and the DVD drive supports the UEFI standard. I just have a basic external Samsung DVD drive and press F12 when the laptop starts. The DVD drive appears second in the boot order list. I then just select it with the up/down arrows, press Enter and the DVD boots.