I found out my dads been watching on my laptop. I do want to confront him about it but how do I stop him?

If he asks to use your computer, bring up notepad and write him a note so he sees it immediatly. Also, delete your history. That way he will know you know about it and that you are uncomfortable. If it gets extreme, you can always say "don't use my computer" and change the pword. He's not wrong by watching it, but its wrong that its on his daughter's computer and that he doesn't attempt to hide it.