every database have to have user associated with it to access it.
You should create a login and assign it the access to the database. Otherwise you can use windows integrated security Or you can provide login and password of user "sa" in the connection string.

If you are able to access the database through your windows account then following would make the connection.
1. create a system DSN on your machine lets say "appDSN".
2. on next tab of dsn creation choose authentication as windows NT authentication and follow the next tabs and instructions(dont forget to choose the database).
3. In your code provide a connection string as "DSN=appDSN"

you should get the connection