By default Windows 7 will remember your PC search queries, and display the most recent examples when searching in Windows Explorer. If you're sharing a PC and don't want everyone to see your searches, simply go to the Registry Editor and look for the following key:
HKEY_CURRENT_USER\Software\Policies\Microsoft\Windows\Explorer
Right-click in the right-hand pane, create a new DWORD value and name it 'DisableSearchBoxSuggestions'. Set the value to '1', exit the Registry Editor and reboot your computer for the changes to take effect.
