QuickTime for Windows 7.7.9 was intended for Windows Vista and Windows 7, not for later versions Windows.
QuickTime for Windows is now unsupported for all versions of Windows.
QuickTime 7.7.9 for Windows - Apple Support
Important: QuickTime 7 for Windows is no longer supported by Apple. New versions of Windows since 2009 have included support for the key media formats, such as H.264 and AAC, that QuickTime 7 enabled. All current Windows web browsers support video without the need for browser plug-ins. If you no longer need QuickTime 7 on your PC, follow the instructions for uninstalling QuickTime 7 for Windows.
Some 3rd party video editing software relied on QuickTime to handle MOV files. Those applications would now be outdated as well, ever since official support was ended.