Hi! Last time I need to post in this thread! 
Yes it did it! At start time I just needed to be very Quick after double clicking the Cubase 10 Icon and pressing Shift+Ctrl+Alt at the same time. It did work! Then I deleted the Program Preferences and now Everything is back to normal with the Drum Editor so I can now see the “Drum Sound List” again.
Thanks very much all!
Now I just need to make Windows to choose Cubase 10 again, and not Cubase 9.5 when opening a Project! I Think I want to keep C9.5 installed even though I’m now going back to C10 again. But thanks all!