I've seen a lot of questions regarding the different denominations within Christianity, but not the religions outside of it. Are they hopelessly lost? And is there any proof that the religion of Christianity is any more real than the others?
Are people outside the Christian religion hopelessly lost? I addressed that in a previous question (unbelievers.html) and in an article in my newsletter, Minutes With Messiah (The Real Question). Essentially, my answer in those places was that if the Bible is God's word to man then God says he has provided His son, Jesus the Messiah, as the only way to get to God. If God chooses to have mercy on those who have never heard the message of grace through the sacrifice of Jesus, I am certainly not going to question God. However, He has said that there is only one way, so to forgive people who try to come to Him in any other way would be to make God a liar.
Does this mean they are hopelessly lost? In no way. Anyone who claims to be a Christian or who is in any other religion and has not "put on Christ" (Galatians 3:27) through immersion in water, who has not had their sins washed away (Acts 22:16), who has not begun a new life separate from their former life of sin (Romans 6), may still be saved if they accept God's grace in the way He specified in the Bible. If that means leaving another religion or a particular Christian denomination, the result is worth it.
All of the above, though, hinges on the other question you ask. "Is there any proof that the religion of Christianity is any more real than the others?" The answer depends on the level of "proof" you require. Since all religions are a matter of faith, and each person has a certain amount of emotional tie to the religion in which he was raised, the amount of proof varies from person to person. (How's that for avoiding a good answer?)
There are a number of books written to "prove" the Bible. There is a whole field of study in "Biblical Evidences" that covers such proofs. These include such things as internal evidence (does the Bible have any inconsistencies or contradictions?), external evidences (does archaeology agree with what was written in the Bible hundreds of years ago?), and less reliably the evidence of people's changed lives. I am convinced in my mind that the Bible is more reliable than other religious texts.
I am convinced in my mind that Christianity is more psychologically satisfying than other religions. That is, it is the only one that seems to me to answer the problems of sin, guilt, where I came from and where I am going after this life. (And I have studied the major world religions to some degree, so this is not just some Christian saying this without studying it.) There are thousands of Hindus and Buddhists in India who are convinced every year that Christianity is truer than what they have been taught. That doesn't really prove anything, but it does show that they feel that something is missing in what they have previously believed.
Can I prove Christianity is more real than the others? Possibly not, depending on how much proof one wants and how disposed they are to change. Many people accept the proofs that are available.
This may not really answer your question, but it is the best I can give. The Bible doesn't try to prove itself; it assumes faith from the beginning.