Hi aim trying to install DNN 4.5.1 i keep getting message:

"An error has occurred while establishing a connection to the server.
When connecting to SQL Server 2005, this failure may be caused by the
fact that under the default settings SQL Server does not allow remote
 connections. (provider: SQL Network Interfaces,
error: 26 - Error Locating Server/Instance Specified)"

As a backround, I am using Ms Visual Studio, IIS 5.1, ASP.Net 1.1 and 2.0
SQL Server 2005

Check address, username, password, etc ... and triple-check your connection strings.

If you have SQL Server Management Studio Express, you should use it to try to connect to your database. If you can connect that way, at least you know the right server address, etc.

Are the site and the SQL Server on the same machine?