Word 2003 Freeze all the time?

I am using Office 2003 (Word 2003 in particular) and I have 256 MB Ram, no viruses, no spyware- a supposedly functional PC. Virtual mem is at the correct parameters. When I open up word documents (the largest so far is only 23 pages) and start editing them, Word locks up- and I have to End Now. What could be causing this? Nothing has showed up in the Event Viewer either?!