Optiplex has a password authentication system. I can’t enter into any data or any other screm
Is HDD encrypted? pls upload lock screenshot. If it is BIOS password you can reset it using passwd jumper on motherboard.
I also have a 790 MT but I can't find these password jumpers (or any bios jumpers) in the owner's manual or tech manuals. Could you please tell us which manual and what page it's on ?