mac won't let me log in

I was on my Macbook Pro, doing several things at once (such as watching netflix, Facebook was open, looking at something on microsoft word). I guess it got overworked and completely froze. I could not force quit anything and cmd-opt-esc was not working. So I did a force shutdown. When I turned the computer back on, it started-up fine, but it would not let me log in. I have two accounts: my personal account and a guest account. Whenever I would put in the password to either, it would look like it was loading, the screen would flash, and then it would return me to the log in screen. I could not log on.

I tried several things to resolve this. First I did a safe boot. Then I repaired the disk utilities and permissions. Then I reset the PRAM. Nothing worked. I would have reinstalled the Mac OSX software, but I do not have wi-fi at the moment. My last attempt was to reset the passwords for the accounts. Luckily, this allowed me to log into the guest account. However, my personal account still won't load when I try to log on.

Please help me find a solution to this problem! I am very frustrated! Thank you.