The boss recently upgraded our Microsoft Office from 2000 to 2012 when he purchased new systems (finally!) I've been able to get my Autotext entries moved from 2000 to 2010 (by way of many forum searches and a friend's Word 2003) and it works fine for new documents. The problem is that we have over 500 Word 2000 documents on the server that are the "boilerplate" for forms and letters that we have to submit to various agencies on a regular basis and when I open one of these documents, the autotext doesn't work. I can, of course, use Insert/Quickparts/Autotext, but, contrary to its name, it is NOT Quick! (Especially having to scroll through my list of 50 autotext entries.)

How do I get autotext to work with an old document?

Since you can insert it from the menu, I take it you mean that the floating pop-up tool-tip is not displaying.

First, you can use the F3 key. You type the name of the AT entry (or at least 4 unique characters from the beginning of the name) and press the F3 key. Your AT will insert.

Or, you put the AT entries into the attached template for a document or into the normal.dotm template. I suspect that in your upgrade the linkages between existing documents and their templates was broken. You can repair that linkage under the Developer Tab on the Document Template button.