• The best way is this, simple steps.
• erase the hdd, you did,(Dban'd)
• run F12 diag, ePSA make sure hdd passes all tests.(if not pass doomed HDD)
• get windows 10  64bit, from MS, off their free down load  page get the media builder. (use other PC yours is dead. the link below covers that too....
• using the builder, make the USB stick  with w10 installer.  8GB stick min.  use the 64bit method.
• move stick to dead PC, 3020Mt,l  and boot the stick make sure safe boot is off in BIOS or it will never boot the stick (or use F12 and find stick and click it and it boots the stick)
• boot the USB install stick and then do as MS tells you.

OK we learn now it is  a Dell 3020MT, full sized mini tower, MT.

and you Dban erased the whole boot drive, so there is NO OS now and that ends free w10 update doing that.

 all dell sevice partitions are gone and all windows same.

so what you do is get the w10-64bit from MS,  free down load page.

and install it, let windows 10 installer do all the setups for partitions automatically, do not try to interfere with that.

just click next, next and so on...

3020MT, same as mine

run ePSA first power on, hammer F12 and pick diagnostics,

that maker sure the OLD HDD is good, and MUST BE GOOD,

then install w10 -64bit fresh.

the no boot device is because you erased the whole HDD< there is no boot files on that drive it is BLANK AND EMPTY now./

The PC is Optiplex 3020 tower. But I already downloaded Windows 10 pro 64 bit, and is working properly.

google "how to install windows 10 fresh",  (zillion hits)

Old systems need DVD instead of USB drive because current versions of windows do not fit on FAT32 media.  Current version of WIN10 supported 1809 1903 1909 does not fit onto usb FAT32 media.

EXFAT and NTFS are not supported for install.

https://www.dell.com/support/article/us/en/04/sln313422/windows-10-iso-contains-wim-file-that-is-big-for-fat32-file-system?lang=en

The workaround is to install WIN10 with the I do not have a key option via OEM system builder dvd.

https://www.newegg.com/microsoft-windows-10-pro-64-bit-reinstall-recovery-disc-only-no-license-key-included/p/N82E16832350238

https://www.dell.com/support/article/us/en/04/sln297920/reset-or-reinstall-windows-10-on-your-dell-computer?lang=en

MS covers all that no need worry 4GB LIMIT ON FAT 32. (see steps and vast pitfalls here)

You do not need to format the USB flash drive, before using the Media Creation Tool.

it will do NTFS. all by itself and is covered at Microsoft the the ends of the earth,.

that is correct the installs do not fit on any CD made,

the Media Creation Tool.  allows you use dual install version of USB,  w10 32 and 64bit so you are ready for any job.

step 3 at MS states and I quote"  so the STICK is blank there is no fat32  on any blank stick)

A blank USB flash drive with at least 8GB of space or blank DVD (and DVD burner) if you want to create media. We recommend using a blank USB or blank DVD, because any content on it will be deleted.

IMO , avoid DVD-R burned media.

MS Media Creation Tool , as stated above, MS tells you who step by step, on 2nd PC, that runs ok for sure.

Go to walmart,  on the rack grab a USB memory stick there, 8GB or larger, take it home and use the tool.

Wallmart, 2 sticks in a pack are $9.88, 16GB, click free store pickup.

free means ship cost free,

Your HDD is erased now, so there is no other way...