If I haven't fired you yet, it's because I'm still firing your mom in bed.
Find some service that allows you to play online against people. This trick doesn't work very well in real life.
1. Open the chess game on your computer, and set the difficulty to max.
2. Find a game online against someone, and make sure your opponent goes first.
3. Mimic whatever move the opponent makes on the local game you have open.
4. Whatever move the max difficulty AI makes is the move you use against your online opponent.
By simply acting as a rudimentary catalyst, you gain the power of a maximum difficulty computer A.I. without even knowing anything about chess! You only need to be able to interpret moves in reverse to accurately mimic them between the games*.
*=Your local Chess game against the computer is supposed to be from the view of your opponent since you're mimicking his moves. Because of this, the pieces will move in the opposite directions.