@Pixey I've tried one again. Uninstall Paint.NET, follow their instructions and then install it. Same result... I swear I have followed all of your instructions (twice *sobs*)
@Rick Yeah I was thinking it was because of updates but they are all done, even the minors. The reboot was my first try. I just repaired it. Same result.
I'm going crazy. Should I wait for the next update ?