1 & 2) Acceptable grammatically, but both sentences sound pretty crazy.
3) This is closer to what you're trying to say, but I'd write it like this:
"I am trying to cut down on my Internet usage."
4) The second sentence makes sense, but it's a little awkward. My suggestion:
"You will run many people over if you drive it."
5) I'm not sure what you're trying to say here. Do you mean that you're playfully punching someone?