If you're having trouble beating the computer, try this trick. If you answer a question wrong you can block the computer players from answering by pressing A, B and C simultaneously.
Block Opponent Method 2
If you're having trouble beating the computer, there is a way to make them not type in an answer. You can only do this to the player to the right of you, player 1 does it to player 2, player 2 to player 3. All you have to do is, wait till they buzz in. Once they buzz in hold buttons A, B, and C on your controller this should keep the computer from answering once he buzzes in. This works on 1 and 2 player mode, (player 2 can do it to the computer in 2 player mode).