I think I know exactly what your talking about. So when you start the task manager, all you get is a box with the CPU usage and usage history. There are no tabs at the top, am I correct? What you must do to solve this problem is double click on the small area of space between cpu usage history and the top of the window. That should bring back the normal task manager window with the applications, processes, performance and networking tabs on the top plus the file, options, view etc. menus.