Hi,
I'm sorry you are having these issues. Ondra was suggesting disabling/uninstalling V-ray purely as a troubleshooting step so we can see if there is maybe some incompatibility.
Which version of V-ray do you have installed and do you have any other 3rd party plugins installed?
Secondly is your Windows up to date, and are you running the latest graphics drivers? Sometimes outdated drivers can cause some strange behaviour like this.
Lastly for the moment, are you able to see Corona in the list of active renderers and are you able to start a render?
Thanks,
Rowan