Starting a few days ago, I am facing a very weird issue here on my Windows 8.1 workstation. I am unable to start programs or applications that require administrator privileges. This makes my PC completely unusable at the moment, because I cannot even run "taskmgr.exe" or edit user profiles (which is the reason, I am asking). The only thing working are "usual" programs, like my browser.
What happens whenever I am trying to start a program as administrator is, that there's a horribly long timeout where nothing happens, followed by the message quoted below:
Windows cannot find 'C:\Windows\system32\taskmgr.exe'. Make sure you typed the name correctly, and then try again.
I found many sites suggesting many things... things like:
sfc /scannow
dism /Online /Cleanup-Image /RestoreHealth
runas /user:Administrator /profile "cmd.exe"
or enabling the built-in administrator
net /user:administrator /active:yes
However, all of these approaches are requesting administrator privileges and thus are not working.
Is there any way, I can try to fix this problem without reinstalling Windows (which appears to be my last option at the moment...)?