WIth respect to your qstn. and our sister & brother Moneera & Qadeem, what they told are correct. All Prophet (Peace be upon them) came with same message of Oneness of Allah (Tawheed) but the peoples tried to destroy or change or ammend the beliefs/Religous laws according to peoples wish & will at living time of prophets and after them also. And in the time of other prophets (peace be upon them) and their srciputures, it didnt told tat they are the last prophet. That means still prophets to come. But in Quran allah says Muhammed(peace be upon him) is the last messenger and Quran is the last guide for the human kind. note the point here, Allah says Quran is the only guide to whole human kind,not only for muslims. And as Allah says in the quran that he will protect this Quran until the day of judgement with out changing a single dot. if you check the First Quran - till this time. nobody cant change its single dot.Allahu Akbarwalillaaaahi Hamdh. This statement is the one of the Unique miracle of Quran, is approved by world's most Historical & Research related peoples.
Brother Quershi still lot of miracles are there,....i wil give you insha allah

Holy QUran 2:216) Perhaps you May Dislike Something Which Is Really Good for you or Like Something Bad for you, but Allah Knows(What Is Best for you) & You Do Not(know)