When you begin to receive this error message when you open your Task Manager
or if after pressing the CTRL+SHIFT+ESC key respectively you donot see a task manager popup.
It might be a virus infection or your admin applied a registry restriction.TO FIX THIS
Type regedit in RUN dialog box or Start Menu Search box and press Enter. It'll open Registry Editor. If Registry editor is also disabled, then follow instructions below
Now go to following keys one by one:
and look for a DWORD value "DisableTaskMgr" in right-side pane. If you find it, delete it.
3. That's it. Now Task Manager will be enabled.
PS: If you are not familiar with editing the registry, then you can use ready-made registry script to do the task automatically. Download following ZIP file, extract it and then run the extracted .REG file. It'll ask for confirmation, accept it:lDownload here