Honestech Inc. went out of business or stopped supporting consumer products years ago. You cannot buy a legitimate serial key from the company anymore. While the software is "abandoned," it is not "public domain." Most "serial" lists circulating on YouTube or sketchy websites are either:
The software is not officially supported on Windows 10 or 11. While it may run in "Compatibility Mode," users are often encouraged to seek newer alternatives or contact the Honestech developer for updated options. Black and White Video: