No, the Kai's Power Goo tools are not available for Windows 8.1. According to the information found on the Internet, the tools have been acquired by Corel and all the versions released afterwards were available through selected channels. To find information about the software, access the Contact US section on Corel website: http://www.corel.com/us/contact-us/
Get in touch with the developers and they should provide additional information.
