PhotoQt can be installed on Windows (64-Bit) using this installer: PhotoQt v4.2 (64-Bit) (checksums)
How to get EPS/AI support in Windows?
PhotoQt uses ImageMagick in order to render a large range of image formats. ImageMagick, in turn, relies on GhostScript to render EPS/AI files. Thus, in order to enable support for them, GhostScript needs to be installed on your computer. You can download the official installer from the GhostScript website right here. Make sure to restart your computer after installing GhostScript, otherwise it might not get picked up by your system.
When launching the installer, you might be greeted by a warning stating that "Windows protected your PC" (the so-called Microsoft SmartScreen).
In order to run the installer, simply click on "More info" and a button "Run anyway" will appear near the bottom.
You can verify the authenticity of the installer by checking the Publisher, it should say Open Source Developer, Lukas Spies.
Over time, as more and more people install PhotoQt, this warning will start to disappear.