Apple quit supporting QuickTime on Windows at the end of last year(2015).
Sine then, several exploits have been identified that allow malicious code to run when a user clicks on a QuickTime video.
These include the ability to craft a short url that exposes personal info.
Many Security analysts (and Apple) are highly recommending that you remove QuickTime from all Windows machines.
Maybe the backlash from this will force Apple to reconsider dropping Windows support of QuickTime.
http://blog.trendmicro.com/urgent-call-action-uninstall-quicktime-windows-today/