problems with graphics in office xp

Graphics in Office XP apps appear choped or incomplete, this happens with vectorials or bitmaps as well. If I change the zoom they appear complete but when I try to zoom in and move up and down problems start. I also work with Corel and Pagemaker but the problem seems to be specially with Word, Powerpoint and Excel, are not OK at all but they work better with graphics than Word
My PC is an AT compatible Pentium IV 2.4 GHZ, 512 RAM, Graphic Card, Graphic Card NVidia Riva TNT2 Model 64, 32 MB Graphic Memory
should I add more Graph memory or there is anything else I should do? Thanks for your help