Win10 no matter what you open, it prompts: "Cannot use the built-in administrator account to open" How to do

first step, hold down the win key, which is Windows+R, Windows key is the graphic button with square (Tianzi), Alt next to. After pressing, enter: secpol.msc as shown below:
After the end, come to the “Local Security Policy Editor”, and then open: Security Settings > Local Policies > Security Options> User Account Control: The administrative approval mode for the built-in administrator account. Then double-click to change it to: Enabled, click Apply, then click OK. As shown below:

The above, after being enabled, open: Control Panel ——System and Security——Change User Account Control. Set the slider to the default. That's it. As shown below:
Finally, you can.