Login problem

Hello apple fans!

First time writing in this forum, and for a bad motive.

For about 2/3 days ago, every time i start my mbp, and he enters the desktop area, loading all the files, the usual stuff after entering the password, he goes back to the password window. All of this after a minute or so i started my mbp.

Can anyone help me on this?!

Does anybody knows some equal story?

P.S: the warranty runs out in this december. lolol.

Thanks in advanced.

Have you tried doing all the normal stuff? Cleaning cache's, repairing permissions, etc?

already done that, and have uninstalled a recent program which may had cause some system files be in conflict...or something, i've too turned off the password at the login, and it keeps doing the same, enters in the osx, and does like a small reboot, or a instant rewind lol. late today gonna go with a full format. first one since i've got my mbp since 2006 lol, it's time to "wash the face". thanks anyway, and will post the results later.

ps: i'm sorry if there's a lack of consistancy in my english

well, nothing like "washing the face" of my mbp, good as new!!