How to solve this Irfanview problem with Win !0 once and for all?

I transferred to Windows 10 some time ago, but because my older computer kept crashing, I installed Windows 7 again.

Now I have a new computer with Windows 10 -- there are no updates for Windows 7 any more -- but I have the same problem as before: the system opens pictures in Microsoft's poor, paltry and idiotic photo program instead of Irfanview, if I click on the picture's shortcut.

Of course I have tried to change the extensions in Irfanview, but it does not help. I have also run the troubleshooting program of MS.

It does not help.

I have a vague memory that I already solved this problem when I was using Windows 10 for some time on my old computer.

How to solve this problem once and for all?

(And if you begin to speak about Linux now, I label you as a hopeless idiot who cannot keep to the point/subject, and I will say it aloud. DID I ASK ANYTHING ABOUT LINUX? NO, SO DON'T SPEAK ABOUT LINUX. Ok, if you want to speak about Linux now, give me the money for a new Linux computer and give me a version of Linux that does not have that stupid terminal. Better still if you don't speak anything about Linux now, so you won't reveal your stupidity.)

In the past I sometimes used that Xnview, but I did not like it. I have not found any picture program that is nearly as good as Irfanview as a simple, no-nonsense image viewer.

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