Burnt Display

I have a new 27"iMac and have been working on some word documents today with both Adobe Bridge and photoshop open underneath. When I closed down Word I noticed the documents had 'burnt' themselves into the screen and against the dark Adobe programmes behind. I restarted the iMac but I the document images are still visible in the same place. Is this normal??? Surely I now have to get this fixed by Apple? Any ideas guys? Thanks.