PowerGallery is a solution, not an extension. You don't need a serial number to use it. Just upload all of the files and folders to a folder on your website and run the installation program per the getting started guide.
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.