I still had my W7 SSD drive to work with and at the same time a new SSD-clone drive for upgrading to W10 as an experiment.
Now I am back with C10+W10 working just fine now after a lot of tweaks and experiments.
The upgrade to Windows 10(PRO) from Home W7 did turn out very well unexpected, I even have a lot more space left on my C-drive. It cleaned up a lot of W7 apparently. Also my FireWire-Hardware works troublefree.
The main problem with C10 under Windows10 was to not be able to open older projects(In C9.5 no problem, so I kept this version installede offcourse), which turned out to be a couple of plugins(which ones are mentioned enough on the forum already).
Newly made Projects were fine untill those plugins were loaded, then a Cubase crash took place.
I came across the tip to insert the Soundtoys Microshift plugin in as a Controlroom insert. I did this, disabled the plugin and now Cubase starts up everytime with that plugin as an inserts so it only has to be done once.
Now every “trouble-plugin” loads just fine and works as it should, no problems at all. And no need for J-Bridge anymore which I also tried( I had this already for some older vst-iinstruments)
So now I am a happy C10/W10 user ready for the future.
And offcourse I already made a new systemcopy of that C-drive