How can I stop screen refreshing and start it again? Anyone???

I wrote a chess prog, and to check for checkmate/stalemate, it makes every legal move for the opponent until they aren't in check (or it declares game over).

Problem is, the screen is flashy while pieces rapidly move around screen. I want to turn this off while checking the position (which should also speed up processing), then turn on again when done.

I am using images for the pieces. Any helpful ideas would be GREATLY appreciated.

~seaweed