Locked out of Windows 10: login no longer shows Administrator, but only an account that I never used

I'm providing this answer as an alternative to watching OP's video and in case the video ever goes down.

It sounds like you're looking to enable the administrator account again. If you cannot sign into Windows at all, have no other boot devices, and want to use no software - do the following.

1. Click/Tap on the Power button under the Start Menu or on the lower right-hand side of the Login screen, press and hold the Shift key, and click/tap on Restart. This will open a command prompt at boot.

Then type:

net user Administrator /active:yes

If for some reason that doesn't work, do the following:

2. In the command prompt, type regedit, and press Enter.

3. In the left pane of Registry Editor, click/tap on the HKEY_LOCAL_MACHINE key.

4. Click/tap on File (menu bar), and on Load Hive.

5. Open the drive (ex: D ) that you have Windows 10 installed on, and browse to the location below. NOTE: The drive letter (ex: C) will not always be the same at boot as it is from within Windows 10.

            D:\Windows\System32\config
   

6. Select the SAM file, and click/tap on Open.
7. In the Load Hive dialog, type REM_SAM, and click/tap on OK.
8. In the left pane of Registry Editor, navigate to and open the key: HKEY_LOCAL_MACHINE\REM_SAM\SAM\Domains\Accounts\Users\000001F4
9. In the right pane of the 000001F4 key, double click/tap on the F binary value to modify it.
10. In line 0038, change 11 to 10, click/tap on OK.
11. Close Registry Editor and the command prompt.
12. Click/tap on Continue to startup back in Windows 10.

NOTE: To disable the Administrator account simply reverse Step 10.

you need to have the Windows (7|8|8.1) install media available.

1. Start your PC off the (Disk|USB|HDD) that contains the install media
2. Once loaded, press Shift+F10. This will open a command prompt
3. Run the following commands in order:

diskpart list vol

1. Once you find the right volume (your C: drive (it may have a different drive letter)), run exit
2. Now, run D: where D is your drive letter.
3. Run cd \Windows\System32
4. Run ren Utilman.exe Utilman_old.exe
5. Run copy cmd.exe Utilman.exe
6. Reboot

Once you get to the logon screen, click the Accessibility Options icon. Once the Command Prompt opens, run these commands, replacing user_to_change with the user you want to reset the password of:

net user user_to_change *

Enter a new password, enter it again (you won't see it) and log in. You can now go back to C:\Windows\System32 and delete the Utilman.exe that we made, and rename Utilman_old.exe to Utilman.exe

For those who are looking for answers:

I followed this video until Command Prompt after login screen (5:05). https://www.youtube.com/watch?v=0dfEd4HZyV4

Then executed this command in opened command prompt.

c:\>net user Administrator /active:yes

And then restart the system. After reboot, it showed Administrator account and I am able to login. Don't forget to rename the executables back to their original form.

Windows 10

Methods for getting a failed Administrative account to work are great assuming you are already logged in as an administrator. I found a method that works when you initially had a good password but Windows became corrupted and would not allow entry of that password.

You can be in any user account and click on the Windows 10 restart button while holding down the shift key.

The computer restarts with many options. Select “Troubleshoot”. Select “Advanced Options”. Note you will also have the option of “Reset PC” but save that for your last resort. Click on “Restore”. Now you need to know your password. In my case I had set my password to “nothing” (literally). I was trying to get the computer to boot without a password. The “blank” entry was correct in my case and the restore options were available. Then I clicked on “Restore”. I also clicked on the more restore options button. I chose a date when things were working great.

The restore said it did not work but in reality it did. I could now log onto my computer as the Administrator by using my 4 digit pin code I had previously established. I believe my 4 digit pin code is only a convenient substitute for the original longer security code.

Windows 10 has a maze of unrefined options and few work. The greatest path for repairs in my opinion might be the Shft/Restart feature. Every time you make a mistake or find a failed solution, you have to reboot and then do the Shft/Restart function again.