IBM 760 EL Screen Display

Hi there,
I'm new to these boards but from what I see you have quite a lot of knowledgable people around here. I recentley purchased a used IBM 760 EL, and just finished loading Win 98 onto it. However, the display (desktop) is not taking up the entire screen. There is about 3/4's of an inch on all sides that just show black and I'm unable to navigate my mouse past these limits. My question is if anyone knows how I set the unit to display onto the entire screen. I have seen pictures that show the entire screen being used, so I'm a little confused as to why mine is not. Any help would be greatly appreciated.
Thanks in advance