SOLVED - No admin account windows 10

I just started with a fresh machine (W10 Pro), and I just ******* it up. I created a user for this computer and it got admin rights. Also, from the users and groups menu, I have seen that there is another "administrator" account there. What I need to do is to have any account with admin rights. I don't have access to a recovery DVD/USB.

So, I've decided to remove admin rights from the user account, but, after doing that, I've realised that the administrator account is blocked, so, I can't change anything, neither create or give admin rights to any account.

I've tried several things from google, like:

Net user administrator /active:yes

which says that I don't have admin rights (yes, windows, I know that). Also, I've tried to use lusrmgr.msc and, again, no admin rights.

I've found also, that I can use shift while rebooting to access some system options, the problem is, whatever I choose, the computer seems to hang and keeps there for a while, doing nothing (no leds blinking) and I need to kill the computer using the power button.

Tried to go to uefi settings using F5, F7, F10 and F11. No luck.

EDIT:

System get stuck while trying to boot from USB/DVD or into UEFI/BOOT options using F9 (as suggested per HP support).

EDIT2: I was able to fix this issue. First, I downloaded a recovery tool from the manufacturer, that boots before the OS and allowed me to disable fastboot "feature". By having the fastboot feature disabled, I was able to use manufactured recovery tool to restore the factory image from the recovery tool.

Thanks everyone for the help.