How can I enable command prompt in bios so that I can open it during windows setup? (laptop won't boot)?

Question

I've been trying to fix my friend's dell laptop. It's been saying no bootable devices and the traditional fixes I've found on the web aren't working. I've decided to reinstall windows to fix this and he doesn't mind losing any files on the computer.

The problem is that in windows setup the hard drive is set to GPT so I can't format it or install windows, I have to go through command prompt to reformat it, however, /diagnosticprompt is set to disabled by default, I don't know how to enable it so that I can reformat the drive and get through windows setup. Please help me figure this out, thank you.

Laptop is a Dell Inspiron 15 5000 series. Photo is the bios I am presented with.

Answer 1

The command prompt is available in Windows PE (the install environment that runs the install program. )  Allow the install program to open, and before you have it perform any functions,  Press SHIFT+F10  This will open a command prompt.  

Answer 2

in BIOS/UEFI, enable boot from USB, then make USB the first boot device.  after that, your hard disk manager program on disk will boot the laptop and let you inspect the boot sector of the HDD.  If your friend is very lucky, the HDD manager program will be able to rewrite the boot sector and he'll recover everything after that.  If he isn't that lucky, it will allow you to reformat the hard drive [thus eliminating the old, malfunctioning boot sector] and write a new boot sector (make disk bootable) -- after which the mobo drivers can be installed [you get these from Dell] and Windows will install.  -- GL  -- grampa

Answer 3

The Command Prompt is part of Windows. The BIOS / UEFI has no control over it. And having GPT partitions shouldn't stop Windows setup from formatting a drive. In fact, computers that use UEFI (as your appears to) are supposed to use GPT.