Well, I also rebuilt the index and now some of the links work, but they are still in the same language.
Any way to change completely the language without having to create a new user???

Doing all this doesn't solve the problem completely, at least to me.
When searching in the start menu for settings, they still appear in the old language instead of the new one, and then nothing...

I'm having some troubles with this. At first I set Windows up with one language. Later I changed it completely (which was not easy, to change it also for default users and the logon screen).
But...