Once the application is loaded and configured it is important for one last test before informing the users the implementation is complete. You are not looking to do a complete system test, just to make sure the executable starts and some primary forms and reports execute correctly, the data converted correctly if a conversion was done, and the version number on the About form matches the expected version implemented. One other thing we like to verify is any ActiveX or COM components used in the application are accessed correctly. Just give it a general once over to give you confidence the installation went as expected.