P Rajanikanth:
The connection string you are using is a DSN-less style string, so you don't need the "dsn=" at the end. So I'm assuming that the following connection string will authenticat a SQL Server login named RK with a password of PWD:
driver=SQL Server;server=houston;uid=RK;pwd=PWD;database=tracker
If so, then the following string will request Windows authentication instead, using the network credentials of the currently logged-in user:
driver=SQL Server;server=houston;uid=;pwd=;database=tracker
A slightly fuller explanation is available here: http://support.microsoft.com/default.aspx?kbid=194641
Cheers,
Chris