To disable the F3 key search capability, perform the following steps:
Start a registry editor (e.g., regedit.exe).
Navigate to the HKEY_CURRENT_USERSoftwarePoliciesMicrosoftInternet ExplorerRestrictions registry subkey. If this subkey doesn’t exist, open the Edit menu and select New, Key to create it.
From the Edit menu, select New, DWORD Value.
Enter the name NoFindFiles, then press Enter.
Double-click the value, set it to 1, then click OK.
Log off and log on for the change to take effect.