I inadvertently linked my Microsoft account with my login in Windows 10 (was just trying to get access to the Xbox screen capture feature). After that, two bad things happened:

1 - I am forced to enter my Microsoft login details every time I want to log in to my computer, which I never did because I don't need that and also hate it;

2 - on top of that, I'm having a really terrible problem because whenever I need to open something and that "User Account Control" pop-up comes up saying "Do you want to allow this app to make changes to your computer?", the ""YES" option is grayed out, i.e., dead, non-clickable. Only the"NO" can be clicked.

So because of that I just can't access a good number of features in Windows 10 -- System Restore, Accounts management and many others -- and even worse, I can't open a whole bunch of programs (like Advanced System Care and most others) and now the worst of all: I can't even install any program in my computer. And I just reset (re-installed) Windows 10 to see if that would solve the problem -- but it didn't -- and I lost all the software I had installed, and now I can't install them back anymore.

So does anyone know why this is happening and how can I solve both the "mandatory password" situation and especially the grayed out "YES" in the User Account Control pop-up?

I will be forever indebted for any help you can give me because I'm just at the end of my rope here, no clue on what to do now, and feeling really desperate.

Thanks in advance.