I am at the end of my tether with this problem and am starting to hate Windows 8 with every fibre in by body.
My daughter is running windows 8.1 but she can do little with the computer as every time she wants to make a change (delete/add programs) it ask for an Administrator's password, however there is nowhere to type in a password and the 'yes' option is greyed out in any case.
She doesn't recall setting up an admin account, although she does have the tendency to click click click and hope for the best.
I searched several forums and whilst many people appear to have this problem, I've yet to find a solution.
Any help would be appreciated