remove Microsoft adminstrator account

first sorry if my english is not good!.
my laptop was recently free upgrade to window 10 with no user and password yet, just administrator. Then when i open microsoft store and trying to download some game it require me to create an microsoft account. I did register one using google email but this account automatic became my new name for old administrator account and always ask for password when the screen is lock. Now i want to remove this account and go back to when the laptop just have administrator with no password and name.
i really upset about this change of window 10. why it have to so complicated, and everything seem to be rely on the internet.
any help!!

i am sorry but there is no option disconnect like you said, also i have a screen shot for u to see what my problem is:

Brink said:

Interesting.

Are you able to create a new local account, change its type to be an administrator, then delete the Microsoft account if you like?

i can create a new local account but can not change that its type to be an administrator.

I used the first option and i can make my new local account to be an administrator but i couldn't delete the other microsoft (administator) account. The system wont let me to do that. The new local account is a new administrator but still can not do anything about the old boss.
Same thing happend to the second option. When i try to change my local account from standard user to administrator, the small box "Change Account Type" will hidden and i can not click on it to save the change.

i bring my laptop to an computer shop and they also can't do anything but only reinstall window is the only way to fix the problem.