How to boot from ISO image in HyperV gen2 with OS already installed?

Question

ISO

Good afternoon!
we have a server with two processors and each with 8 cores with HT. seasoned with 64Gb of RAM.
server 2016 was rolled onto it, on the basis of which HyperV G2 was launched.
about 8 machines installed, but one of the machines had a problem, I forgot the admin password :D.
I found a bunch of different ISO images, all sorts of Hyrens, DiskPart, and even the original ISO from server2016 .... I mount it into the drive, but the system does not start from the image .... nothing at all, I set priorities (the item firmware-boot order), added 2 drives each, .... well, I can’t load from the image in any way, what can you advise?
PS - I forgot to write, I need to reset the admin password

Answer 1

Well, since there are no such options, then tell me options of a different nature.
HyperV has a VHDX virtual disk extension ... which can be mounted on the host machine, now the question is, what can be done with this disk to reset the password? Do not suggest deleting the SAM file, the system will go into a blue screen ....

Answer 2

In the virtual machine settings: firmware
Raise the DVD drive to the very top.
Tried on Win Server 2019