Permission issue-SSH

I faced an issue in my server .Its OS is rhel 5.On one morning when I turned on it its ssh terminal was unable to log in.I tried all known ways but when I typed mu user name and pass word for root its shown that 'login incorrect'.I checked for a solution online and found that a file
/etc/ssh/sshd_config
has a line commented as #PermitRootaccess Yes
Uncommented that one.
Then restarted sshd service

#service sshd restart

but again an error came as

ssh_host_dsa_key  and ssh_host_rsa_key

have permission as 0777 so they are too open .I changed it as 

#chmod 600 ssh_host_dsa_key

#chmod 600 ssh_host_rsa_key

and then

#service sshd restart

#sshd stoping  OK

#sshd starting   OK

How is that,saved my day............................................