Hi Alain thanks for the helpful photo.
To my understanding all previous versions of Seamless3d would need the file User32.dll
Many programs need this common file.
If you can put a copy of this file (make a copy of it do NOT move it) in the same folder that Seamless3d.exe is in, it will be available to seamless when you run seamless.
Ron did not reply to my last message so I do not know if this will work:
Search for a User32.dll file in your C:\Windows\System32 folder and copy (Do NOT move it) it to your C:\Program Files\Seamless3d folder.
If you can't find it in your System32 folder, try searching all folders in your C:\Windows folder.
Some other program on your computer should need this file so it should be in your computer somewhere.
Please let me know if you can find this file or not and what your result is.
best wishes
Thyme