Just install it (you can download from MS at download
Run the tool, pick ‘Add Application’ from the file menu and browse to the ‘setup.exe’ program in the CS3 install folder on the DVD. Once you’ve added the app you can pick tests from the right pane. Open the ‘Compatibility’ node and check HighVersionLie. Right click it after checking it and pick properties. Fill in the above info to mimick win xp sp2 (option: major version 5, minor version 1, build number 2600. Advanced: service pack major 2, service pack minor 1) – you dont need to specify the product type field. Save everything (button on bottom right of app) and then run the installer for CS3 (setup.exe in the photoshop cs3 folder) with the Application Verifier running.