HELP Please ! Can't login .

[OSU <thomas.1037@osu.edu>]

hi,

I am using kernel 2.4.5 with unstable, and was playing around installing 
new software . But in the process I logged off to take a break and was not 
able to log
back in . I can not login as root or myself . Even before I am able to type 
the password I get the error " loging incorrect" . I am able to login as 
root ( with the
correct passwd ) if I boot in single user mode. However in this case I can 
not "su" to any other user or even root . "su" gives the error " su: 
Modules is unknown " . Based on what i found on the web I tried the 
following but none worked :
1) ran ldconfig
2)  ran update-modules
3) Mercylessly deleted all pam related packages except those in "required 
base" which I reinstalled .
4) Tried "adduser" but it failed with "passwd" giving the same error 
"Module is unknown"

How can I reverse these changes and/or find what package is causing the 
problem ?

thanking you
b thomas