Root can log on, user account can't. "Error in service module"
 

Fedora Core 5

I was playing Enigma when I accidentally hit the 'a' key and it killed my marble. (Don't worry if you don't play Enigma; it's only slightly relevant.) In order to see if there were any more keys I should avoid, I began striking them in alphabetical order. Somewhere around 'r' I was logged out and dumped back to the GUI login.

I can log on as root at both GUI and command line. If I try to log on as my user account from the GUI I get an "Authentication failed" window. Clicking OK takes me back to the username prompt. If I try to log on as my user account from the command line I get the error "Error in service module" and the next line is a Username prompt. I've reset the user account password but that has had no effect.

First, anybody know why my walking the alphabet would have kicked me out? Did I hit some magic sequence of keystrokes? Second, how do I undo what I've done? Yes, I know I can create a new user and copy the files, but that's a workaround, not a solution.

looks like an error in your PAM.
try checking/posting your /etc/pam.d/login

/etc/pam.d/login
 

I can post it. I can't check it since I don't know what it does or I'm looking for.

#%PAM-1.0
auth required pam_securetty.so
auth include system-auth
account required pam_nologin.so
account include system-auth
password include system-auth
# pam_selinux.so close should be the first session rule
session required pam_selinux.so close
session include system-auth
session required pam_loginuid.so
session optional pam_console.so
# pam_selinux.so open should be the last session rule
session required pam_selinux.so open

Additional Info
 

Maybe the Enigma / keying information is a false lead.

Prior to this problem I had just installed Enigma. That was my second attempt to use yum to install a program. My first attempt was a 'yum update' after I finally figured out how to pass my credentials to the company proxy server. When the update finally finished, I immediately installed Enigma.

Should I have rebooted after the yum update completed? (Yes, I know that's a rather Windowsish question, but that's where all my experience lies.) Is it possible something in the update is preventing my user account from logging in?