Have you verified by opening the Task Manager that Outlook.exe isn't running
in the processes? Just to ensure that it has completely closed, before we
look at other potential issues.
Also, please verify that the Find box has not been dragged to the desktop.
If neither above are the case, perhaps the Outlook toolbars are corrupted.
What you want to do then is close Outlook (make sure it's not running in the
processes either) and locate the outcmd.dat file (this is hidden so ensure
you are able to view hidden files/folders) and rename it (eg:
outcmd.dat_old). Then open Outlook again to see if this has resolve the
problem.
If this doesn't resolve the problem, does the behaviour still persist if you
open Outlook in safe mode? Start > Run > outlook.exe /safe.