The first thing you need to keep in mind while tracking down your free version of QuickTime Pro is that there are two different versions – one for Mac and one for PC. If you enter a QuickTime Pro code for Mac on your PC, or vice versa, it won't work, so be careful.
Concerned about how what uninstalling QuickTime (https://unite-alzheimer-oblivio.com/content/uploads/files/download/quicktime-pro-activation-key.zip) will do to your computer? Apple's iTunes no longer uses QuickTime (https://unite-alzheimer-oblivio.com/serial-code/?file=8724) and most websites don't require the program for playing videos, so it's safe fore most people to uninstall. There are only a few professional content creation tools for Windows that still require QuickTime (find out).