Some1 help?

Shhnoobie1

i have a laptop sony vaio with a 17.5 inch screen ati radeon 3470 bad fps i say full room 30 40 max

http://www.mobilecomputermag.co.uk/img/fckImages/reviews/2009/09/sony/sony-vgn-fw41-03.jpg

but it has a screen resolution so i can set it to 1600x900 but for some reason i can change to 800x600 1024x768 but wont let me change it to 1600x900 it is there but i cant click on it as it wont let me (its like faded so i cant click on it) i was wondering if any1 has this laptop or knows alot about computers could they help? thanks.