Internet

I'm guessing this wasn't your own computer?

Erm, Roger old boy.....is it in actual fact your computer?
Have you possibly purchased it from a dodgy geezer down the pub recently?
Are or were you actually in your own home at the time, or in someone else's home and on their PC without permission?

If your fingers are tapping a keyboard that your fingers shouldn't be tapping for any reason, you may have good reason to fear that some sort of security programme has sprung into action and posted your fizzog to plod, who may now be on their way to feel your proverbial collar.