What OS can with your PC ???
If it came with windows 8/8.1 then you do not need a Key as it is embedded into the BIOS
After running setup from the ISO - you will have to run MS Updates, to bring to current...
If you can get into the BIOS, but can not change anything - without being prompted for a password.
Then you have an Admin Bios Password...
If you can get to the OS Login Screen - where it asks for a password - then you also have an OS Password...
Now the other issue you appear to have (Due to...
There are 2 types of Admin Passwords - One Is the BIOS Admin Password - The other is an OS Admin Password..
So which is it ??
Bios Passwords are harder to reset and / or to find a viable method to do so.
OS Passwords can be cleared by software or Reinstallation of OS
Open> command prompt (Admin)
type> select disk ? - (? being the disk number assigned to USB)
type> list partition - (should only be 1 partition)
type> select partition 1
Close Command Prompt Windows and Reboot PC From USB
Mount ISO and Copy Contents of ISO to FAT32 Formatted USB
Should use Clean USB -
If using UEFI Mode then just use Boot Menu (F12) usually to Select - UEFI USB
If Using MBR/Legacy Mode - the USB partition will need to be Set as Active - then use Boot Menu Option to Select USB
You need to use the "Windows Recovery Tool - Bootable PE Rescue Disk"
The Link Is In My Sig Below... Or Here > Windows 10 Recovery Tools - Bootable Rescue Disk - Windows 10 Forums
Boot from that Media to give you visible access to the HDD and partitions...
I do see a 20GB Partition labeled as...