.shd3-File opens with Adobe Acrobat Reader

[KandW]

After installing the portable version of SweetHome 3D 5.7 Windows x86 Version , instantly - for no reason - all '.sh3d' files are automatically marked as if they were associated to a '.pdf' file. In other words, when I double-click on a .sh3d file,
Acrobat Reader starts with the following error message: "Adobe Acrobat Reader can not open 'Floor plan_1.04.sh3d' because the file type is not supported".
When I start SweetHome and open a .sh3d file, the file will load correctly. More elegant and faster is of course Double-click on the file.
How can I cancel the wrong link?
Have I downloaded the right version of Sweet Home? The computer runs on Windows 7 - 32 Bit operating system. What does mean -"x86".
Many thanks for your assistance.

[Puybaret]

The portable version doesn't associate .sh3d extension with Sweet Home 3D executables. A search on the web will give you a solution.

[KandW]

Thanks for your advice. I followed your link, and changed File Associations and Extensions. But my input was not accepted. What now?
I wonder why in an earlier program of SweetHome portable I didn't had this problem.