Are you sure Start8 is still running?
If you look in taskmanager there will be Start8 processes if so.
I ask because Windows 8.1 has a start button on the taskbar which opens the Windows 8 fullscreen menu. Additionally if you used Start8 to boot to the desktop then that will remain the case after Start8 is removed as 8.1 added an OS setting for this which is what we use. If you right click on the taskbar and pick properties there is a setting for booting to the desktop or not.