As a first step, I would suggest updating to Windows 10. Keep in mind that Windows 7 is not supported by Microsoft any more, so it doesn't receive new updates. And new updates sometimes affect Corona. Updating Windows is often the easiest solution to various problems.
Other than that, I may be wrong, but I think that displaying the VFB with the rendering content on a render node (3dsmaxcmd, Backburner, etc) would be against Autodesk licensing policy. So that may be the reason as well.