For those still using Microsoft’s now defunct accounts package, Office Accounting, on upgrade to Office 2010 you will find that the new XML style document handling breaks your Office Accounting templates so that you can no longer modify them (although they are still usable)
The fix for this is to use, or re-install, an older version of Office.
If you have not yet installed Office 2010 then when prompted, select CUSTOM install and install 2010 IN ADDITION to your old version. You can then still utilise your old copy of Word to update Accounting templates.
If you on installation of Office 2010 you selected UPGRADE and hence lost your old version, don’t panic. Just reinstall the old copy of Word.
I still use MS Office Accounting for my small business accounts as it is very flexible and much more user friendly than Sage or similar. It is sad that Microsoft no longer support it.