The usual cause is a corrupted normal.dot or corrupted registry entries.
Take a look here for possible troubleshooting steps:

http://word.mvps.org/FAQs/AppErrors/...peningWord.htm

--
Herb Tyson MS MVP
Please respond in the newsgroups so everyone can follow along.
http://www.herbtyson.com
"S Youzba" wrote in message
...
This has been a lingering problem. Everytime I have more than one
document
open in Word 2000, if I close one document, the entire program encounters
a
problem and must shut down. This seems to have occured after I upgraded
from
ME OS to XP Pro. I have tried to reload Office completely and have
downloaded and installed all updates. Any clue of how this can be fixed
or
what is causing the problem. BTW, it does not happen in Excel, or
Powerpoint.