Toshiba Satellite 17" L355-S7812 Gaming...

Question

I just purchased a Satellite series laptop from a local Best Buy retailer. Immediately i was taken by its preformance and am overall impressed, but i would not be here if i did not have a complaint or problem. When i try to change my Toshibas screen resolution, the resolution does not change -- The screen just gets small and black bars coat the sides of it. Whenever i try to play a full-screen video game on this laptop it never fits my screen so i have to work with a tiny box in the center. I would like to know how to really set my games to full-screen and how to change resolution while keeping the whole 17" screen i paid for.