The simple and confident answer to this, however, is to tell them that you have the preserved Bible, the KJV, which is completely without error and can be traced all the way back to the earliest manuscripts we know of, including the Dead Sea Scrolls. When Muslims come to realize that God has, indeed, preserved His words, confidence in the Bible is restored and they are far more apt to listen to what you have to say.
The Quran is nearly a thousand years older than the KJV, and still in its original language, so it is unlikely a Muslim would be convinced by your assertion.