How can i fix my playstation 2 console?

Sometimes when i turn my game on it will start. It will start going all the way through the game. Then when i get all the way to the point when i am about to start playing it will freeze.After it freezes I take the game out and clean it. While I clean it i turn the game off. when i am ready to turn the game on i push the on button but it takes a long time for the game screen to come back on. then when it finally comes on the disc read error comes on or it will say enter a playstation 2 disc. It does this foe any game I put in the playstation 2. Can you tell me how to fix it thank you.
Bye,