Windows 10: Administrator missing problem

I suddenly deleted my administrator account and want to recover it. I cannot find safe boot on advanced options.How can I fix that

:)

 

Administrator level User

Got the laptop. It's a Lenovo G500 so possibly has Lenovo stuff in the way? Anyway, booted it normally and it opens into a regular account without admin privileges. Rebooted it into Recovery mode (per Option 5) and get Lenovo logo and Preparing Automatic Repair message; then Select Account + "You need to sign in as an administrator to continue but there aren't any administrator accounts on this PC". There is an option "Forgot your password or don't see your account?" but selecting that brings up a screen which should list admin accounts but there aren't any. Pressing the only option on that page Restart leads eventually to a BSOD with Stop code: 0xc00002e3 (which I know is misconfigured o/s or missing or damaged system files).

Can anybody suggest next steps in resolving this?

 

Why did the startup window get cleared?

I didn't missed any step, the list was gone and gone , even after using lot of programs the programs were not listed in that list.

 

User Account Control dialog missing Yes button

Problem solved after a lot of fiddling around, by following the solution I linked to above, except:

• To boot into safe mode, I had to press Enter while GRUB was showing (I use a dual-boot system). Just letting it time out with "Windows 10" selected as I usually do would not work, Windows would not boot at all or boot into regular mode.
• In safe mode, I was able to log in as administrator by just leaving the password field empty.
• After resetting the administrator password as suggested, it is no longer empty, Windows changes it to "password", which I luckily found out in a desparate attempt to guess it. I was then able to complete the rest of the steps in the linked article and restore my administrator privileges. Who would have guessed it works like that.