First, I have to say that I solved my problem right now, because I remembered my password.
The problem was that I forgot it a time so I clicked on "Forgot your password". I received the mail, and I clicked on the link to change the password. Then I wrote a new password but when I confirmed it (for good) and I clicked on "Reset password", it just reload the page without confirming anything.
I have do it again and again but nothing happenned.
As I told it at the beginning of the topic, now I remember my old password, but I prefer to tell it, hope that the problem will be solve because I think it could be problmatic if another one forgot his password and never remember it.
Thanks for reading,
P.S.: Sorry for my english level, I am French ;-)