Because Windows 7 ate 9.
Eric Clapton wouldn't drop a bag of cocaine out the window
If you open the windows in a submarine, your problems will begin.
Because he ate too much of them.
He has claw marks on his forehead.
Hey Microsoft, why is there no Windows 9? You've given us 7 and 8, and now you're skipping straight to 10?" "Well, to be completely honest, 7 8 9."
Because they don't do Windows
Because Windows 7 8 9
Because 7 8 9!