Word Freezes


Word is freezing sporadically when I use the scroll bar or the arrow key to move between lines. I searched this site earlier and made the changes suggested to address Word freezing when someone was using one of the tool bars (drawing?). Word worked fine for a few hours, but it has just frozen again. I have Mac OS 10.3.9 on a PowerBook G4. Actually, Word just unfroze after about 5 minutes. The rainbow circle was spinning for 5 minutes, which is what I referred to as freezing. I have only been running Safari 1.3 and Endnote 6.0.2 at the same time. Any ideas why this is happening and how I can fix it? I don't have a strong understanding of computers, other than how to use one that is working fine. So please answer accordingly. Thanks.
What is the exact version of Word you're using and have you applied all available updates from Microsoft?