Color changes when moving mouse pointer

Hi,
I have an issue that, when I move the mouse pointer over the controls of the video (when playing quicktime movies in full screen) that it goes darker and looks a lot better!
But as soon as I move the cursor away from the controls, the image becomes brighter, loses contrast and on the side is a green oder pink stripe.
Funny is, it does that in quicklook too, but not only in full screen!
the weirdest thing ever is... it did that on my old windows machine too!!!!!

I thought when I buy a mac it will go away... but apparently not... very disappointing!

I have googled the whole internet, but apparently I am the only one with this issue... or maybe not?
Can anyone provide any help??