>I modified my applications login routine to call the SQL 2005 instance, and it works from my workstation if I format the SERVER value as ".\SQL2005". But this will only work on my local workstation. On another workstation, that does not have SQL 2005 loaded, I tried to put it in as 192.168.30.36\SQL2005 but it fails. That format even fails on my local workstation.

Use the Surface Area Configuration Manager and be sure the SQL Browser Service is running.