1: Did the problems only start after you upgraded and consequently reinstalled Windows 10.
The problems started about 4 weeks ago, with blue screens every single time I played any game for about 10-15 minutes.
I have had windows 10 since its release. And as far as I can remember there were no updates (windows or drivers) that I did or had before it happened.
After this first crash it was however my first impulse to update all drivers.
2: After upgrading and then reinstalling Windows 10 did you then install all of the latest available 64-bit drivers for the MB and starting with the chipset drivers first.
This is indeed one of the issues I ran into. And as you noted yourself Medion doesn't supply MB drivers for windows 10.
That is also why I am suspecting the motherboard for just being outdated and not supported anymore unfortunately, but I wanted to make sure it was the motherboard before going out buying a new one and still having this problem.
About the java thing, I just now realised I haven't even installed java since I did a clean install of windows 10...
Can't find traces of java anywhere