Turn off the prompt for installing Windows Desktop Search
To avoid being prompted to install Windows Desktop Search each time you open Outlook, do the following:
On the Tools menu, click Options.
Click Other, and then click Advanced Options.
Under General settings, clear the Show prompts to enable Instant Search check box.
Note This check box does not appear if your computer runs Windows Vista, or if your computer runs Microsoft Windows XP and has the Windows Desktop Search components installed.