1) after deleting all partitions - do not create any - allow installation to the unallocated drive space.
2) you may need to download and provide the Mass Storage Driver for you HDD/SDD
3) i've never had to use Rufus to create installation media - Just Fat32 formatted USB
As a DELL Fan - I have never had an issue when updating BIOS...
Also search for Driver by Service Tag....
After you get all dell driver installed then use windows update...
I have a venue pro and the Touch driver was critical to have
there was also some other driver pack that did all the...
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