HELP ME!!!!!!!!!!! Pleez read this!

[sillygiggle03]

I have a HUGE problem. One day i decided i was going to play sims 2. I saw the little intro video and it was working fine. But then when it gets to the loading screen b4 the main menu it crashes! It loads fine at first. But when it gets about 1/4 through the loading bar, when it says "decloryphylizing leaves" the music glitches, then plays normal, but the game freezes. When i do ctrl+alt+del to see if its responding, or minimize the game, a window pops up saying "Application crashed. This application will now terminate" and my game closes!  >:-( If it doesnt freeze at 1/4 it freezes at 3/4 through when it says "Calculatung snowball trajectories." 
     
    Pleeeez Help me!!! Post any ideas to make it work!!!!!!