There is no evidence to support the claims that Jesus existed as a living being on Earth. This article gives the details to support this statement. There are no contemporaneous writings or other evidence to support the claim that he did. There are a few mentions of Christians, but none that mention the man now known as Jesus Christ or any of the supposed events of his life.
The New Testament is just a collection of stories written long after the supposed events took place. And even the writers of the New Testament make no claims of first or even second-hand reports. Additionally, many of the stories about Jesus sound suspiciously similar to older stories in the Jewish tradition and the stories told about Greek, Roman, Egyptian, and Persian gods.
I don't understand why so many think that Jesus, as portrayed in the New Testament Bible stories, was trying to start a new religion. He was trying to reform Judaism. It was Paul and later writers who created a new religion that came to be called Christianity.
If you believe that Jesus existed because "the Bible tells you so," then you must also believe in Zeus and Athena and the rest of Greek mythology because Homer wrote about them in The Odyssey. He reports these happenings as true events.
The existence of Jesus Christ cannot be proven either true or false. It cannot be proven true because there is no evidence and it cannot be proven false because there could always be some new evidence found. The best we can do is say that, based on all the information that we have now, it is far more likely that Jesus did not exist. Richard Carrier, in his exhaustively researched book (cited in the article), says that his best guess puts the odds for the existence of Jesus at 1 in 12,000.