Ok, my first guess would be a poorly configured monitor... Is this a CRT or LCD? Well, go into the menu on the monitor (There should be a button on the monitor that says "menu") and try changing the moire settings. If it's an LCD and your on XP, turning on ClearType fonts may help (Right click desktop, properties, appearance, effects. Change smoothing type to ClearType.)
Well, if that doesn't work... Try updating the video card drivers. If that doesn't work, I'd put my bet that your friend's monitor simply sucks