The Queen does not descend from the Norman Kings as her family are German and they came to Britain several centuries after the end of the Norman dynasty. The dynasty that followed the Normans were the Plantagenets who were not only Kings of England but Dukes of Anjou. They kept their lands and their name.
Reply to above: The Queen does descend from the Norman Kings. Her ancestor the Hanover monarch George I (German) only came to the throne because he was descended from the first Stuart James I (Scottish), who came to the throne because he was descended from the first Tudor Henry VII (Welsh), who only came to the throne because he was descended from John of Gaunt, the son of the Plantagenet Edward III who was the great-great-great-great-great-great-grandson of William the Conqueror (Norman).