You're using Microsoft Office Word 2000 and not Word that comes with Microsoft Works?
If so:
For labels:
Hit Tools-Envelopes & Labels, choose Labels tab. Hit Options and choose your label number (or equivalent if not Avery). Hit OK. Hit New Document. If you don't see anything on your document, hit View-Page Layout; hit View-Zoom and choose Page Width; hit Table-Show gridlines (if it says Hide gridlines, then your gridlines should already be showing). The gridlines are the borders of the labels (which is nothing more than a table layout), but the borders are set to no color so they don't print. This way, you can type into individual labels anytime you want. If you use it a lot, then save it as a Document Template (*.dot) called "labels". Do not change the Save in location. Close the file. Everytime you want to use those labels, hit File-New and double-click "labels".
For envelopes:
I'm not sure if you want to use the envelopes tab or not. I do not use it, I think it's nothing but a pain in the buttski. So I create a template for those too so that I can type as many as I want any time I want and not have to keep hitting Tools-Envelopes...blah, blah. You can save your printer setup this way too. Many people complain that it doesn't save the feed direction for their printer. I tell them how to create the template. Let me know if you want instructions.