Plasma won't work as a display for my laptop...

In the past I have been able to use my plasma tv as a display for my laptop with relative ease. Basically I just connect it up via a vga cord and hit Fn/F4 which shoots the image up to the plasma.

Each time you hit Fn/F4 it kind of scrolls through having the picture on both the laptop and plasma then to just having it on the plasma and finally to just having it on the laptop.

When the picture is on both the laptop AND plasma and you try and open a video file – the video file window (windows media player for example) will open and sound will work (assuming that is also connected properly) but the video will remain black.

To fix this I just keep hitting Fn/F4 till the picture is fully on the plasma and now when I play the video file it plays both sound and video perfectly.

Here is where it gets interesting…

My flatmate hooked his laptop up to the plasma in a similar fashion but he has a more modern computer and it automatically detected the new plasma without having to press Fn/F4 or any other combination of buttons.

He can play video just fine.

This is where it gets wierd…

Now when I tried to connect my laptop as I have always done and press Fn/F4 it still scrolls through the various combinations of display but when it gets to fully being on the plasma the entire screen just goes black.

It will show the shared version of plasma and laptop and do the whole sound but no vision thing for video files but it won’t completely utilize the plasma screen and thus play the video files properly.

That’s wierd right?

Any help would be greatly appreciated.

Pete.