Hi PMenage,
Have you tried to run it in compatibility mode?
If system restore is available, we could recover the machine to a previous point.
Considering this software is developed by yourself and the environment is a little old, we may need to re-develop the software. For a developing issue, it is recommended to ask for help from our MSDN forum.
MSDN forum
https://social.msdn.microsoft.com/Forums/en-US/home
Best regards
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