Connect A PC To The Local Network but NOT On The Internet

I want to "Connect A PC To The Local Network but NOT On The Internet.". I don't want the computer connecting to the Internet at all but yet can see other computers on the network and use shared printers and files/folders. I don't want any hackers able to ping the computer or see it at all from the Internet. I would like to do this by not making any changes to my router. Can I just setup a static...