The first logon thing is called "First Logon Animation" and it's both an HTML file for the glowing stuff and the .exe for well, probably the text They are located inside C:\Windows\System32\oobe (on systems that HAVE the oobe, not including OSes older than 8 or 7??? i dunno)
I once deleted something in registry that broke my windows just like in your video, i wanted to get rid off some games, cuz even if you deleted the game there is still a couple thing related to it in registry.
yes, i am kinda shocked myself because i thought i would have to wait like 1 year to get 100 subscribers, but i literally got 230 subs in 2 months thank you by the way