Windows 10: Second hand PC administrator

I bought a second hand PC and I can't remove the administrator and there are malwares such as TeamViewer and Ghost ToolBox. Anyone help me

:)

 

Is it advisable/useful to have a second (full) Administrator account?

Firstly, I should say that someone suggested this Forum to me and it's one of the most useful things that I have come across on the Internet!
I read somewhere that one way to safeguard your system is to create a second Administrator account in addition to the one that is built-in in Windows, so that should there be a problem with the "original" Administrator account you would use the second one to restore the first one.
If this is indeed advisable, what are the steps to do it? I presume that I should password-protect the second Administrator account.
Would I have the second Administrator account always enabled and the original Administrator account always disabled?

 

Administrator level User

Use Option Five again, but this time boot from a Windows 10 install usb or recovery drive. You only get asked to select an administrator account if you boot from the system's own Advanced Startup.

 

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?