Resolution problem

Hi!

I bought a new Notebook and i wanted to change the CrossFire resolution. But i can change the resolution only to 1024 x 768. I can't change it to 1280 x 800(wide), 1440 x 900 (wide) or 1680 x 1050 (wide). If i change it, for example in 1280 x 800 (wide) , i get always the error:

Selected screen resolution is not supported my your monitor.
Can't change status.

The problem is that i could change it on my old Notebook. But my new Notebook is much better.

Help me please