I have a dedicated server with sshd and no telnet. For the past week I have had a user be able to login with sshd no problem. All of a sudden yesterday when he enters his password he gets Permission Denied or Access Denied. I can login with my admin account just fine. I tried creating a new user and it wouldnt allow the new account access either. Sorry for being so vague but I am a newbie to ssh. I also forgot to mention I allowed his username in the sshd_config.

but you checked your logs and they said...?

Do you have /etc/hosts.allow or /etc/hosts.deny setup? You could be restricting by IPs... but since you are a newbie, maybe not. But you are giving too little info so we can only guess....

Check the /etc/passwd file and see what shell he has enabled for his username. If it's something like /sbin/nologin or /bin/false then edit that file and change it to /bin/bash for example.