Cannot connect to SQL Server database regardless of connection string I'm having a tough time to connect to a local SQL Server instance within a C# app.  I can connect to external databases on other servers, but I need to be able to use my own local database.

The exception I get is:


  {"Login failed for user 'ASTROAdmin'."}


There isn't really any more info within the exception, so I don't know if the account doesn't exist, if the password is bad, if the database doesn't exist, etc.  The connection string I'm using is:


  connectionString="Server=MIKE-LAPTOP;Initial
  Catalog=ASTRO_PROD;Integrated Security=False;User
  ID=ASTROAdmin;Password=password;Persist Security Info=True;Type System
  Version=SQL Server 2008;Application Name=OpsMgr;"


I've also ran the following on the server:

ALTER LOGIN [ASTROAdmin] WITH PASSWORD=N'password'


So the password should be fine.

I've been trying different values (such as . and localhost) for Server and also using Data Source= instead, but I get the same exception no matter what.  My theory is that there are multiple instances of SQL Server on this machine, like perhaps SQL Server Express.

Also, if I run the SQL Profiler tool, I don't see anything come up as it tries to connect.  No data what-so-ever.

What's the best way to continue to diagnose this problem?  Thanks!
If you have access to SQL Server Management Studio, then attempt a logon to MIKE-LAPTOP with your provided credentials.  Can you connect?  Any errors thrown?  That will eliminate the possibility of password/permissions.  

You mentioned that there could be multiple SQL instances.  Depending on configurations, you may need to specify the instance name and/or port number.

Such as:

MIKE-LAPTOP\sql2008 
MIKE-LAPTOP\sql2008,1433