Can't re-register QuickTime 7 Pro

I bought QuickTime Pro 7 way back in 2006, and have used it over the years. I had to replace my Mac Pro with a newer version, and I reinstalled all my software on this computer. When I brought up QuickTime 7, the Pro features were not enabled. I went back into my email to enter the registration code that always worked for me in the past, but when I clicked on the 'Buy' button, I was directed to a server, quicktimepro.apple.com that does not exist any more. So how do I get this back and working?