minecraft launher does not start

hi
when i start minecraft launcher there is no launcher and i discovered it was beacause of error code 5 and i looked it up and saw i should just rename some files but when i got to rename them there were no files and i could play the game perfectly fine before but now i for some reason cant i noticed this begining to happen after i tried to install the new launcher and then none would work so i ran magic launcher but with the release of 1.12 i cant play the newest version any longer if you now how to fix it please help