Can I set Office to just use the old document format all the time and forget about these new extensions?
Yes. You can choose “Save As…” and select the Office 97-2004 format, then click the Options button and set Office 97-2004 as the default format. We recommend biting the bullet and using the new format, and only reverting to the “Save As…” solution if someone you share files with, has difficulty reading the new file format.
