I am using VS.net 2005. I have downloaded a sable database and I try to connect to it within VB.NET. Unfortunatly I cannot connect to the database. En error saying that I have not install support for .MDF file. I don't know what this is. Can you help me please.

An Mdf file is a SQL Server file and can't be accessed directly. It has to be attached to SQL Server and connected to via an ODBC connection, or ADO connection string.