First: welcome here second: should have been posted in applications forum
Now to your problem. Really any window is missing the entire tool- and menubar or only Windows Explorer? Are you perhaps running fullscreen mode? If so press F11 to switch back.
If this doesn't help check out this link (http://www.kellys-korner-xp.com/xp_t.htm), scroll down to "toolbars missing".
If this still doesn't help systemrestore or systemfile checker (type: sfc /Scannow in the run dialog) may be solutions.