If you can't use interop or the OpenXML standards (because no docx support in Word 2000) you may want to take a look at an external library that doesn't use COM or similar. At our office we use the Aspose components which does this for us but unfortunately this library is not free of charge :(
The component can be found here http://www.aspose.com/.net/word-component.aspx
Alternatively, free of charge you may also want to check NetOffice which supports Office 2000 and is free of charge and uses the model you are probably familiar with. See http://netoffice.codeplex.com for more information