Well you're not going to be using a .txt for SQL connections

Okay, try this.
Remove the DSN using the ODBC applet, don't simply try to remove it in the registry yourself.

Then start regshot and perform these tasks

1. Run 1st shot
2. Setup the ODBC DSN as though it is going to be live, real.
3. Run 2nd shot
4. Compare
5. Post the entire Compare here

Once you post the compare I'll write a UDF type script for you to use.