Recently, Apple made an announcement that everyone should be familiar with.
They announced that they are no longer supporting QuickTime for Microsoft Windows. In particular, they are not going to fix any more security vulnerabilities in it.
There are already two known security vulnerabilities with QuickTime for Windows now. Trend Micro Zero Day Initiative reported them to Apple last November and instead of fixing them, Apples official response was that people should uninstall QuickTime for Windows.