Whenever I try to do anything, like install a program, open some files, I get an UAC warning saying: :"To continue, type an administrator password", but there's no textbox where I can type the password and Yes button is disabled. I found a solution on the forum http://www.tomshardware.co.uk/faq/id-2122704/user-account-control-doesnt-enter-password-click-windows-windows.html, but I can't enter Safe mode whatever I try, I never get an option to enter safe mode and I can't use msconfig cause UAC blocked it. What can I do?