Q: How do I remove Photoshop CS3 Beta? / Do I need to remove Photoshop CS3 Beta before installing the final version?
must uninstall the beta before installing the final version. In Windows, this is done via Add/Remove Programs in Control Panel. A de-activation of the Photoshop Beta before uninstalling and a clean-up of the Windows registry after uninstall is adviced.
If you experience problems or conflicts after trying this method, it may be necessary for you to use the CS3Clean script. Use the CS3Clean script as a last resort, and follow instructions carefully. Note: The script will remove all folders and registry entries belonging to Photoshop CS3 (beta) including all custom actions, brushes, plug-ins etc. in place in these folders.
See this Knowledge Base article for more information: