Nope, Bill Gate didn't invent the Internet. It is the U.S. department of defense that is who started it. The Internet started back in 70's!
Internet Society (ISOC) All About The Internet: History of the Internet
During mid 80's U.S. post office actually invented E-mail, but because U.S. Post office didn't have patience to start with profit, so they sold to MCI. That company patiently wait for about 2 years before profit start kick in, and boom!