Get a command prompt by going to Start menu -> Search -> Type "cmd" -> then click cmd under the "programs" heading.
Now type (exactly as it appears): "Good evening friend's computer! It's finally time to give you back! Please delete all the porn I downloaded and make sure I didn't give you any viruses."
You might get an unrecognized command error. If so, you're on your own and will have to remember where you stored all that porn and delete it manually.