In game Menus disappearing

In game Menus disappearing

While i am in the game, trying to navigate my way between anything, ie build to buy to family, or whatever, the menu disappears. but as soon as i hit an arrow key it will reappear, then as soon as it stops moving the menu will dissappear.

I am using a Mac G5.... can anyone help me

ps there are no modifications to the game... i have already tried to totally erase all my Sims 2 data and reinstall it