OK, the fact that you don't have to log in is not important, you're booting from a "rescue disk" to access the Command Prompt, whereas I accessed things differently. With a Rescue Disk you don't need to log in because there are no "accounts" to log into on the disk.
So my next question is this .....
When the command window opens on your computer, what does it say at the top of it ?
It should have a title at the top saying ...
Administrator X:\Windows\System32\cmd.exe
And the cursor inside the command window should be flashing against .... X:\Windows\System32
If it has anything different, please let me know exactly what it is.