Deleted Administrator For Windows 10

[Janice Barnes]

I accidentally deleted my administrator account. how do I get it back?

 

[Trouble]

IF there are no other accounts on the system, that are members of the local administrators group then you will need to obtain the installation media and boot from it.
The installation media can be obtained through either of these two resources.

https://www.microsoft.com/en-us/software-download/techbench
OR
http://www.microsoft.com/en-us/software-download/windows10

Once you have the ISO, you can use ImgBurn to burn it to a DVD or Rufus to burn it to a USB ThumbDrive, either of which you can use to boot your computer.

When you've managed to boot from the installation media you need to click the Repair Your PC link on the second page after the Choose a Language and Keyboard layout page.
That should get you to the Advanced Troubleshooting options and subsequently to the Command Prompt or just hold the Shift Key and strike the F10 key at the language and keyboard screen, that will also produce a command prompt, THEN......
Follow the steps in this article to enable the hidden administrator account.
http://pureinfotech.com/2015/11/20/how-reset-windows-10-forgotten-password-regain-access-computer/
From there you should be able to either fix your old admin account or create a new one.