Web pages don't cover entire screen with Vista

[heidiho]

Some web pages cover my entire 17" monitor but most of them don't. It's like watching television on letter box and I don't like it. This web site is full page but a few examples are Veteran's Administration; KOA campground: yahoo answers web page and a lot of my games are only half. I can go to lower right corner and change to 150% view and it'll be ok but I have to do that for each page I go to. Also full screen top right corner only makes it smaller. There's got to be an easier way. Is there a way to make all the web sites the same size so that they cover my whole screen? I have no problems with my desktop which is XP. Everything fits the monitor.
Also how do I change the background color on web pages? Everything is white. My background color for this letter is a pale yellow which is good but all web page backgrounds are white.
I'm using Vista Premium Laptop with IE 8.
Thanks for your time and have a nice evening.