Sims 2 neightbourhood purple flash

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when i downloaded the sims 2 (all of it) it was fine. But when i went inside the game, i found out it was flashing purple and when it snows it turned red. the walls and the lake was all red and flashing from red to black. I don't know what's wrong and its VERY ugly!!! I read on some other blog sites, it was some old flash mod but i don't think so and i don't want to start up anything like a virus and my dad helped me fix it so i think its safer to let him try but i want to know HOW to fix it. Do i have to download anything or what? And when i bought a chinese sims 2 version, (like an accident) can i change it back (i can't read or write alot of chinese words even though i'm asian)... I'm in major trouble and i need lots of reponses and comments!!!