Same thing happened to me maybe 15 years ago when I was learning Linux as a 12 year old. Some thing opened vi because my $EDITOR var wasn't set. I spent a good 30 minutes trying to close vi! I tried Ctrl-c (which I had just learned), but it wasn't working. I also tried Ctrl-d! In the end, I just hard cycled my machine and deleted the binary. Looking back, this is probably the reason why I use emacs. I think I be a vi user if this hadn't happened to me!