I just went through this myself in order to address an issue in the Log viewer "Error trying to generate shortcut icon: System.ArgumentException: Illegal character..." I had to run a repair on the Altiris Notification Server 6.0 and on the latest Notification Server 6.0 SP3 update. After doing that I was unable to log into the console, thought it was an IIS issue as well. I rebooted the server again, opened up the 6.0 console on the NS and I was prompted to go through the setup wizard. I put in the SQL application credentials and the rest of the settings were retained and once the wizard completed I was able to get back in fine.