There's an App called Whatchanged...
Start on a machine without the ODBC connection...
Run Whatchanged, and let it scan the registry.
Add the ODBC conneciton, and let it scan again to see where it is (may be) putting the password in the registry...
http://www.majorgeeks.com/mg/getmirror/what_changed,1.html -- It's an older App, but it still works.