While trying to run a Windows-application with a private DB (SQL Server 2005 Express Edition) on a client machine (Window Vista), I have regard with a problem entering the master DB.

After a few seconds I've found this one: http://www.microsoft.com/sql/howtobuy/sqlonvista.mspx
Download and Install SQL Server 2005 SP1, that should solve the problems.

Update 1:

• Pay attention that the sp1\sp2 don't need an SQL Server to be installed - it hold the whole package within.

Update 2:

• Windows Vista have strict privileges within its program files directory, so while deploying the DB There it holds it as a read-only DB.
  Put your DB in the SQL Server Directory to solve this problem.