Odd External Display Issue

[btrav13]

I have a 23 inch Samsung LED that I am using with a new 15 inch i7 MBP. Everything was working wonderfully until today when I had to power my MBP off due to a program lockup. Now the picture on the MPB that used to fill the Samsung screen no longer does. It leaves about 1 1/2 inches of black on either side of the Samsung that is just dead space. Some of my programs now hang over into those areas and you cannot see them fully. Why would it have changed like this just due to a power off and how do I get it back to displaying the full screen on the Samsung? I have toyed with this for over an hour now and am getting nowhere.

 

[btrav13]

As an extra issue I've just notice (stupid me)...my MBP used to go dark, even with the lid up, and not display what was on the Samsung as long as I had used the option "mirror displays". Now, the images are on both at the same time.