Answer:
   
   The question above is a typical one asked by Christian Missionaries.
   The answer is easy, if one understands Jewish beliefs.
   
   Jews do not believe that the Messiah is a part of G-d, or Divine in
   any way, more than any other person. Jews look only to G-d for our
   salvation, and when the time comes for G-d to bring the anointed king,
   then it shall happen. Jews do not concern ourselves with the messiah's
   identity, for the messiah is a person and the messiah's coming does
   not change our relationship with G-d. Jews do not accept the notion
   that Scripture "foretells" that G-d would robe Himself in flesh; in
   fact, to Jews, this idea is idolatry, and we stand against it.
   
   The reason why Jews do not accept Jesus as the messiah is
   straightforward: he did not meet the requirements in the job
   requisition! G-d outlined these requirements in the Bible. The key
   aspect of proof is in the state of the world.According to the Bible,
   amongst the most mission of the messiah includes returning the world
   to return to G-d and G-d's teachings; restoring the royal dynasty to
   the descendants of David; overseeing the rebuilding of Jerusalem,
   including the Temple; gathering the Jewish people from all over the
   world and bringing them home to the Land of Israel; reestablishing the
   Sanhedrin; restoring the sacrificial system, the Sabbatical year and
   Jubilee. This simply has not happened. Judaism has no notion of the
   messiah not doing these things on the first visit, let along needing a
   second visit to do these things. Whenever these things are described
   in the Tanach, the description says that the messiah will come and do
   these things--once.
   
   Oh, you want specifics? According to Torah, the Messiah will:
   
    1. Ezekiel 37:26-28: Build the Third Temple
    2. Isaiah 43:5-6: Gather all Jews back to the Land of Israel
    3. Isaiah 2:4: Usher in an era of world peace, and end all hatred,
       oppression, suffering and disease. "Nation shall not lift up sword
       against nation, neither shall man learn war anymore."
    4. Zechariah 14:9: Spread universal knowledge of the G-d of Israel -
       uniting the entire human race as one: "G-d will be King over all
       the world--on that day, G-d will be One and His Name will be One"
       
   Jesus fulfilled none of these messianic prophecies. Additionally:
     * Jesus was not a prophet. Prophecy could only exist in Israel when
       the land is inhabited by a majority of world Jewry. During the
       time of Ezra (~300 BCE) the majority of Jews refused to move from
       Babylon to Israel, thus prophecy ended upon the death of the last
       prophets (Haggai, Zechariah and Malachi). Jesus appeared on the
       scene approximately 350 years after prophecy had ended.
     * Jesus was not descended from King David. Per Genesis 49:10 and
       Isaiah 11:1, the Messiah must be descended on his father's side
       from King David. However, according to the Christian claim that
       Jesus was the product of a virgin birth, he had no father -- and
       thus could not have possibly fulfilled the messianic requirement
       of being descended on his father's side from King David! The
       Christian idea of a virgin birth is derived from a verse in Isaiah
       describing an "alma" as giving birth. The word "alma" has always
       meant a young woman, but Christian theologians came centuries
       later and translated it as "virgin." This accords Jesus' birth
       with the first century pagan idea of mortals being impregnated by
       G-ds.
     * Tradition teaches that the Messiah will lead the Jewish people to
       full Torah observance. Deut. 13:1-4 states that all mitzvahs
       remain binding forever, and anyone coming to change the Torah is
       immediately identified as a false prophet. Throughout the New
       Testament, Jesus contradicts the Torah and states its commandments
       are no longer applicable. (John 1:45 and 9:16, Acts 3:22 and 7:37)
       
   In Christianity, the role of the messiah was redefined in order to fit
   the man's career as written by his followers. As Jesus was said to
   have been resurrected, the Bible was examined with the purpose of
   finding evidence that the messiah would be killed without bringing
   peace to the world or redemption to Israel. There was therefore the
   expectation of a second coming, at which time Jesus would carry out
   the task expected of the messiah (because he obviously didn't do it
   the first time). This also required creation of an explanation for the
   first coming and its catastrophic end. The net result of all of this
   was to shift the function of the messiah from a visible level where it
   could be tested (as in Tanach, what Christians call the "Old
   Testament") to an invisible level where it could not. As a result of
   this reworking, the messiah's goal the first time around was changed
   from the redemption of Israel to the atonement for "original sin". A
   reworking of Biblical themes.
   
   There were also mistakes with respect to Jesus's death and its
   foretelling. Psalms 22:17 says, "Like a lion, they are at my hands and
   feet." The Hebrew word ki-ari (like a lion) is grammatically similar
   to the word "gouged." Thus Christianity reads the verse as a reference
   to crucifixion: "They pierced my hands and feet." Christians also
   claim that Isaiah 53 refers to Jesus. Actually, Isaiah 53 directly
   follows the theme of chapter 52, describing the exile and redemption
   of the Jewish people. The singular form is used because the Jews
   ("Israel") are regarded as one unit (this occurs elsewhere in Torah).
   
   For Jews, if the Tanach's requirements for the messiah have not been
   fulfilled, then there can only be one explanation: he has not yet
   come. To Jews, who were often subjected to mockery and contempt when
   asked where their messiah was, this was a painful statement to make.
   But it was inescapable. As our forefather's said: Ani M'amin: I
   believe with complete faith in the coming of the messiah; and though
   he may tarry I shall wait for him every day."
   
   Furthermore, Christianity contradicts Jewish theology. In
   Christianity, the notion of "Trinity" breaks G-d into three separate
   beings: The Father, the Son and the Holy Ghost (Matthew 28:19).
   However, the basis of Jewish belief is captured in the Shema: "Hear O
   Israel, the Lord our G-d, the Lord is ONE" (Deut. 6:4). Jews declare
   the One-ness of G-d every day, writing it on doorposts (Mezuzah), and
   binding it to the hand and head (Tefillin). This statement of G-d's
   One-ness is the first words a Jewish child is taught to say, and the
   last words uttered before he dies. In Jewish law, worship of a
   three-part G-d is considered idolatry -- one of the three cardinal
   sins which a Jew should rather give up his life than transgress. This
   explains why during the Inquisitions and throughout history, Jews gave
   up their lives rather than convert.
   
   Furthermore, Christians believe that G-d came down to earth in human
   form, as Jesus said: "I and the Father are one" (John 10:30). However,
   in Judaism, the fundamental idea is that G-d is Incorporial, meaning
   G-d has no physical form. In Judaism, G-d is Eternal, above time,
   Infinite, beyond space. G-d cannot be born, and cannot die. Saying
   that G-d assumes human form makes G-d small, diminishing both G-d's
   Unity and Divinity. The Torah says: "G-d is not a mortal" (Numbers
   23:19). Judaism says that the Messiah will be born of human parents,
   with normal physical attributes just like other people. He will not be
   a demigod, and will not possess supernatural qualities. In fact, an
   individual is alive in every generation with the capacity to step into
   the role of the Messiah. (Maimonides - Laws of Kings 11:3)
   
   In Christian belief, prayer must be directed through an intermediary.
   Jesus himself is an intermediary, as Jesus said: "No man cometh unto
   the Father but by me." In Judaism, prayer is a totally private matter,
   between each individual and G-d. Torah says, "G-d is near to all who
   call unto Him" (Psalms 145:18). Further, the Ten Commandments state:
   "You shall have no other gods before me," meaning that it is forbidden
   to set up a mediator between G-d and man. (Maimonides - Laws of
   Idolatry ch. 1)
   
   Lastly, in Christianity, the physical world is viewed as an evil to be
   avoided. Mary is portrayed as a virgin. Priests and nuns are celibate.
   Monasteries are in remote, secluded locations. In Judaism, the belief
   is that G-d created the physical world not to frustrate us, but for
   our pleasure. Jewish spirituality comes through grappling with the
   mundane world in a way that uplifts and elevates. Sex in the proper
   context is one of the holiest acts we can perform. The Talmud says if
   a person has the opportunity to taste a new fruit and refuses to do
   so, he will have to account for that in the World-to-Come. Jewish
   rabbinical schools teach how to live amidst the bustle of commercial
   activity. Jews don't retreat from life, we elevate it.
   
   So what do Jews say about Jesus, if he wasn't the messiah. The
   historical Jesus (not the mangod Christianity made him into)
   accomplished a great deal in turning people away from idolatry and
   towards a more authentic knowledge of G-d. But he has no special role
   to Judaism, in fact, no role at all.