Why Moses is not Sargon I? This is not going to be a question about the Bible or God but I believe that is related with the Christianity. I believe in God, I came to my Savior several years ago but recently a friend sent me a website (Spanish language) where the author presented some evidence about how "Sargon I" and Moses have a similar history (see the section around image #15). 

I know we have to defend our faith, so how can I refute that argument about Sargon and Moses?
Claims

There are no sources that claim Moses and Sargon of Akkad are the same person, but many sources do claim that the stories are similar enough to suggest one borrowing from the other. The most notable being that the information we have about Sargon places him in a basket sent down a river, just as Exodus does with Moses.


  Similarities between the Neo-Assyrian Sargon Birth Legend and other infant birth exposures in ancient literature, including Moses, Karna, and Oedipus, were noted by Otto Rank in 1909. The legend was also studied in detail by Brian Lewis, and compared with a number of different examples of the infant birth exposure motif found in European and Asian folk tales. He discusses a possible archetype form, giving particular attention to the Sargon legend and the account of the birth of Moses. Joseph Campbell has also made such comparisons.
  Sargon of Akkad - Comparisons in Ancient Literature - Wikipedia


Specifically, a story of Sargon's birth places him in a basket and has him sent down the river, much like Moses' birth as detailed in Exodus.

Sources of these tales

Moses' life, including the stories of his birth, are recorded in Exodus. Different scholars will date the writing of Exodus more conservatively or more liberally from the 15th Century BC to the 7th Century BC. The chronology of the story places Moses in the 15th Century BC, however.

Sargon lived and ruled in the 23rd Century BC. However, it seems that most of what we know about him, including the events of his story similar to Moses', are from cuneiform tablets written in about 650 BC called The Legend of Sargon. These tablets were discovered as part of the library of Ashurbanipal at Nineveh in the 19th Century AD.

Analysis

There is no doubt that Sargon lived long before Moses. However, neither has surviving stories that clearly out-date the other, therefore there is no bibliographic evidence that the later one is borrowing from the earlier one. But, there is good scholarship in dating the writing of Exodus to the 7th Century BC and the tablets we have of Sargon are also from the 7th Century BC. Additionally, we know that Israel, the originator of the stories of Moses, was in the area where the stories of Sargon would have been kept and read in the 7th Century BC. This should lead one to conclude that the story of Sargon influenced the story of Moses.

Conversely, There is decent scholarship in dating the writing of Exodus much earlier than the 7th Century BC. This lends credence to the idea that Exodus influenced The Legend of Sargon.

Like most claims of authorship, dating, and syncretism, this comes down to which bits of evidence you find more convincing. My impression is that most scholars  find the evidence suggesting that The Legend of Sargon influenced Exodus the most convincing. So if you want to "prove" that the stories of Moses influenced the stories of Sargon, you need to convince the other party that Exodus was written earlier than the 7th Century BC and that there is little reason to think that the tablets we have of The Legend of Sargon is not a copy of earlier writings.

Miscellaneous Sources


The Legend of Sargon of Akkad - Ancient History Encyclopedia
The Legend of Sargon Translation - Fordham University
Book of Exodus - Authorship - Wikipedia
Mosaic Authorship - Wikipedia