If you are trying to get your DB table's data in client application then the SQL server or a
client installed SQL server edition is required to install on client's system to access data using .mdb file.
--or--
Use a client-server infrastructure where client can connect to your SQL server via LAN. In this case server name would be in "System_IP/DB_Name" format.
And in client application connection string should be as below
string constr="Data Source=<server_name>; Initial Catalog=<db_name>; User Id=<login_name>; Password=<password>";
And if SQL server is configured using windows authentication in place of User Id and Password use
Integrated Security=true;