This only happens with one program which I have used for years, and only has happened since Windows 8.1. Manufacturer denies that it is their problem and insists it is my computer. Anyone else get this error or does anyone know how to correct it? I use this program (or did) heavily for many years.

Hi Retired,

What  program are you using? Did it work well with Windows 8.1 machine before?
If the program never worked with Windows 8.1, we should troubleshoot the compatibility issue.
We could check the compatibility issue here.
Compatibility Center
https://www.microsoft.com/en-us/windows/compatibility/CompatCenter/Home

According to the error messages, we could refer to the following link to have a fix.
PRB: ASP Error 80004005 "Data Source Name Not Found"
https://support.microsoft.com/en-us/kb/306345

If the program needs to acccess the SQL, I hope the following link will be useful.
[Microsoft][ODBC Driver Manager] Data source name not found and no default driver specified
https://www.youtube.com/watch?v=_5QEEQhpRbQ
NOTE: This response contains a reference to a third party World Wide Web site. Microsoft is providing this information as a convenience to you. Microsoft does not control these sites and has not tested any software or information found on these sites.
What steps have the third party program support offered to troubleshoot?
We could off the the ODBC (Control Panel\System and Security\Administrative Tools\ODBC data)configuration ideas to see if there is any update from the third party support.

Best regards