For those of you who like closure, I will present my results. In summary, I was able to produce valid and reconciled 1040X amended returns for tax years 2004 - 2016. 2014-2016 was easily done using the up-to-date TurboTax software I already had on my Win10 machine. Thanks to
@dmertz I was able to update the CD TurboTax software I had reloaded for 2009 - 2013, again on my Win10 machine. Unfortunately, 2004 - 2008 TurboTax versions would not successfully load on Win10, so I had to create a "Virtual Windows XP PC" inside Win10 and reload the 2004 - 2008 CD TurboTax software there. Thanks to
@rjs I was then able to update 2008 tax year software on the Win XP virtual PC. I never found any updates for 2004 - 2007, so I went to a VERY OLD backup of my previous PC (which still had the final versions of 2004 - 2007 TurboTax programs loaded) and copied the Forms subdirectory over the one loaded from the CD. Using that "kludged" version of the 2004 - 2007 tax years software worked well enough for me to produce 1040X amended returns that reconciled to my original file copies of those tax years. I WOULD NOT RECOMMEND THIS PROCESS TO ANYONE, but it worked for me. Now, I hope never to have to file these.
