As a first step, try running Word in safe mode (From the Windows Start button, select Run, and type winword.exe /a). If it works OK then, the problem is most likely due to a faulty 3rd-Party Addin. Bluetooth drivers, for example, are notorious for causing problems. I f Word runs OK in safe mode, re-start it then disable all 3rd-Party Addins. Microsoft's Silverlight is also incompatible with Office 2000 (uninstall this via the Windows Control Panel if its installed). Re-enable the Addins one at a time and try the things that provoked the crash, until you find which Addin's the culprit, then disable that one again.
If running Word in safe mode doesn't fix the problem, Word may have a corrupt registry key. In that case, close all Office programs then, from the Windows Start Button, click Run, type
Regedit, then click OK. In Regedit, navigate to:
HKEY_CURRENT_USER\Software\Microsoft\Office\9.0\Wo rd\Data
and delete the key. Word will re-create in upon re-starting. Note that you'll lose any existing customisations.
Failing the above, you might also try the further manual steps at this link:
http://support.microsoft.com/kb/921541/en-us. Although it only refers to office 2003 & later, the Office 2003 instructions are equally applicable to Office 2000.