Questions relating to drawing in chess
A draw is a game in which neither player wins. In the case of a draw, each player is usually ascribed 0.5 points, i.e. half a win. (Recently, some tournaments have experimented with a soccer/football style of scoring - in which a player receives 3 points for winning, 1 point for drawing and 0 points for losing - as an attempt to encourage decisive results.)
A draw can occur because of
threefold repetition. This occurs when the same position occurs three times in the course of a game, with the same player to move each time.
the criteria of the fifty-move rule being met. This occurs when fifty consecutive moves by each side have been played, and those moves do not include a capture or a pawn move.
insufficient material. This occurs when neither player has enough forces to checkmate the opponent or when no sequence of legal moves can lead to checkmate. The possible combinations which are insufficient material are: (1) King vs. King, (2) King and minor piece (Knight or Bishop) vs. King and optional minor piece, and (3) King and two Knights vs. King (optional: two Knights or single minor piece).
For more information on draws, see the Wikipedia article.