To check the screen resolution right click anywhere on you desktop, select properties at the bottom of the pop up nand go to settings. may have play around as it will also change text size etc
I have this effect slightly as well. I have 1024x780 and with the image maximised it is about 2mm wider than my screen. This gives a horizontal scrollbar with a tiny amount of moment. It has always been on this version of AB
The AB page is 1,000 pixels wide. Allowing for the border round Internet Explorer, plus the vertical scrollbar on the right, it requires a minimum screen width of 1,028 pixels (which is a pretty stupid figure, as is doesn't correlate to anything at all!). So it just won't quite fit on a 1024x768 screen, although you can, of course use Ctrl and the minus key on the numeric pad to zoom out.
Well, you can't have it both ways AOG. Either it's small and fits, or it's big and it don't.
As has been suggested, your only other alternative is to buy a bigger screen.