[ubuntu] Tried everything cant login to admin account!

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http://ubuntuforums.org – I have Ubuntu 12.04 LTS installed and have read many articles on finding a way to change the admin password as i forgot it after installing it a while ago. I have 2 users on this comp which i know the pass to 1 but the admin 1st user i can no longer get into. I have tried many ways like going through grub, root and trying to unmount. i have had it tell me several times that the password has been updated successfully and i still cant login. If i am in my other user and i try to install things and use the password that i changed it to it works but actually logging into the main user account wont (Hardware)