Thomas is playing Tic-Tac-Toe with a computer. It is the computer's turn to place an "x" on the board. If the computer makes its moves at random in the open spaces, what is the chance it will win on this move?

Answer 1

Not enough information.
Is this the computer's third move, fourth move ?
After all, one must have at least 3 pieces on the board to win.

Here is a good analysis of the game.

http://en.wikipedia.org/wiki/Tic-tac-toe#Number_of_possible_games

Answer 2

wikipedia is always wrong dud.

(from the dying drawn hand puppets morice and morica)