Building a test front-end is an excellent approach. One of the changes in Win7 and later is that the ODBC DSN must be done for the current User, while in older versions you could define a System one and get it to work. But as long as the DSN name doesn't change, I would expect the connection to work after the upgrade. I presume Integrated Security is being used, not SQL Server defined user logins - if not, you may want to investigate, though it sounds like you don't have much control over the network.