what should I do to convince my Windows Vista to use XnView?

[secarica]

I have two computers, one with XP and one with Vista. In installed XnView on both.
On XP, after clicking "The most used" associations in program preferences, everything works fine (well, except some crashes when encountering movie files, but this is other thing). By clicking (say) a .jpg, it opens in XnView.
I have done the same on Vista, but the images does not load with XnView, it still open with default system viewer.

On XP, if I right click on .jpg image, I can see Open With -> Windows Picture and Fax Viewer / Opera Internet Browser / Paint / XnView for Windows.
On Vista, the same Open With on a similar .jpg will show -> Windows Photo Gallery (or something like that, I am on a translated Windows) / Opera Internet Browser / Paint. No trace of XnView.

What should I do in Vista to show XnView in file open association ?

Cristi

[xnview]

To be able to change associations, you must start XnView with admin rights

[secarica]

Worked, thank you.

Cristi