iMac not logging probably due to keychains problem iMac OS X Lion.

I have 2 accounts with password.

On the first account, I was messing up the keychains thing. If I recall correctly, I think I deleted all private keys I had and added exported keys from a different Mac (long story).

I have logged out.

Now, when I try to login to the first account, I write the password, the screen goes blank for a moment, and then goes back to the login screen. No popup messages at all etc.

I can, however, enter my second account, probably because I didn't mess with the keychains in it.

So I need help figuring out how can I.. err, login to the first account and fix this keychains problem?

I was suggested to enter safe mode, following the steps here: iMac Lion not logging in but it doesn't seem to work.
You need to boot your Mac into Recovery HD mode, and then use the Reset Password utility utility to reset your log-in password.

Shut down your Mac, and press the power button. As soon as you heard the start-up chime, hold down the Option key. Images of more than one boot volume will show up. Use the arrow keys to select Recovery HD. When bootup in Recovery HD completes, you can find the Reset Password utility in the menu commands. Sorry, I don't have a screen shot.