Hello,
thank you again to all of you trying to help me getting out of this mess...a big part of it was ny own fault with not continuelybdoing backups of my system....that's a lesson I learned for sure.
On the other side,
win10 did regularly system restore imagies as it should. But win10 last build 1607 was faulty in this point. There was a bug in win10 makeing it impossible to restore the system images again.....That's crazy isn't ? The restore function doesn't work! And Microsoft did know it! They announced it on their support pages. Just with the creators update the bug should be fixed.