Okay, after yhe install I arrived to the Grub Boot, enter the e and add "radeon.modeset=0", hit control x, then try to boot and in the load proccess all the letters looks fuzzy, and when I try to open a terminal (Ctrl+Alt+F1) It looks fuzzy also. Appears and disappears (I have to hit Ctrl+alt+F1 so it appears again. I have tried to enter my autentication a zillion time and it says the same a other install tries: Authentication Failure. I'm not such a moron,, I've tried everything that this instrucions detail...