Windows 10 boot fails error '0xc000021a'

Okay, so I did something stupid yesterday. I was not able to delete some stupid files from C:/ so decided to take ownership of the drive. Midway through the process, I got numerous errors which I simply skipped. My desktop and recycle bin corrupted and the stock apps deleted itself. My desktop also deleted all the icons. I got the error "Access is Denied to Desktop " so I tried reverting everything back.

Well, that just spoiled stuff. After restarting, it stuck on this infinite loop. Microsoft tells me that they can't help me because I don't have my product key.

Please help me here.