You can use ALT_ENTER on a keyboard to switch MP between "full screen" and "windowed" states.Is there a way to set up Mediaportal to record video whilst in a window as opposed to using the full screen.
You can also click the "minimise to task bar" icon (on the window title bar) if you don't want MP on the screen at all while you are using the system for something else.
Finally, there is a configuration option that you can specify to cause MP to start in a window, instead of starting full screen.
-- from CyberSimian in the UK