Mobile Phone Monitor

Here is my problem, I have a friend who used to have his flat screen tv hooked up as a monitor to his windows xp home edition and it worked fine he plugged it in and it came right on just had to change the display settings.  Well he switched to xp pro and when it plugs in and fires up the computer it displays the windows xp pro screen and then gets weird and no screen.  Is there anything I could do to get it to recognize the tv like home did?