Okay, i managed to sort out the PAM Problem.
What we did is as below and some steps as above reply(moving passwd and shadow file to the orginal place)
on the FC4 server, rpm -qa | grep pam
Okay i remember that the dependency that got installed was pam-0.99.7.1-5.fc7.
Using another server that was on fc7, we compared the diff between authconfig, login and sshd with the one on fc4 server, found out that fc7 server also do not also have the pam_stack.so file as well but was working without any problem.
So we ftp in the authconfig, login and sshd file into the FC4.
Voila, able to login via sshd and console.
Thanks for the help given.