When you try to find “Task Manager Top Tabs Missing” from google then most like you will get the link http://answers.microsoft.com/en-us/windows/forum/windows_xp-windows_programs/task-manager-top-tabs-missing/9a76add0-8ae8-4cdf-bbcc-650dd68fc383.
The answer is:
To regain the Tabs and information, double-click on the outside border of the window
Now the question is where is the border? The border is actually here: