A client of mine has a brand new Dell Inspiron 3646 win 8 PC that he put a windows password on and forgot the password. I have a bootable DVD app that resets the password. I restarted the PC, pressed f12, that goes into the boot manager. The current boot mode is secure UEFI. The DVD drive is not listed. If I select Change boot device setting, and select Legacy boot mode, save and reboot, it restarts and says no boot device found.