Minecraft launcher starts but does not reflect the game properly

Dear team

 

We have uploaded Minecraft from minecraft.net to PC, however when son son starts the launcher, it does only appear at Task bar but nothing more. I can see the game open while trying to switch between the active windows trough Alt+Tab but I can not activate the window of Minecraft. 

I reinstralled Minecraft couple of times today however it did not help and the problem is still the same and still there.