Are you running Windows XP?
EDIT
Try this:
Task Manager Menu Bar and Tabs Are Not Visible in Windows XP
View products that this article applies to.
This article was previously published under Q314227
For a Microsoft Windows 2000 version of this article, see
193050.
SYMPTOMS
The menu bar and tabs may not be visible in Task Manager.
CAUSE
This behavior may occur if Task Manager is running in Tiny Footprint mode. If you double-click the empty space in the border around the tabs, Task Manager switches to this mode.
RESOLUTION
To switch Task Manager to its typical display mode, double-click the top border of the window.
MORE INFORMATION
When Task Manager is running in Tiny Footprint mode, you can resize the window.