Windows 7 is automatically saves all the recent search results done by the users.  If the computer is shared by others, you might not want others to see your past searches. There is a way in which you can disable search history display in Windows 7. However, you cannot disable search history display in Windows 7 Home editions because the Group Policy Editor is not available in the Home versions. Follow these steps to disable search history display in Windows 7 :

Type the "gpedit.msc" in the search box of the Start menu and Press Enter. This will open the Local Group Policy Editor.

Find More - http://www.freewindowstips.com/2010/09/09/how-to-disable-search-history-display-in-windows-7/