I just built an SQL server box, with both 2005/2008, visual studios 05/08 all side by side. The 2008 works flawlessly, can log into it and everything. The 05 on the other hand is acting like it doesn't even exsist. (these are all enterprise edition, 64bit) I am using SQL Server Management Studio 2005 to log into these (from the local machines). This box is not on a domain it is standalone, and I am using the local admin account to log into the servers. Any thoughts as to why I cannot access / log into the 2005 server?

Nevermind figured it. most basic screw up. When installing SQL 2005 I choose all default settings. Including default instance. When I installed 2008 I named the instance. I was assuming the default instance name for 2005 was MSSQLSERVER since I named the other one MSSQLSERVER08, turned out to be just the local machine name.