I think the reason why it still displays the wb version 4 as a separate program is that some people don't have the hardware necessary for wb5. The reason that for you, both are displayed as being installed is a kinda glitch; DO NOT uninstall wb4 because the two uninstallers (wb4 and wb5) are linked to the same files, if you uninstall wb4, wb5 will get uninstalled as well, and vice versa.