The Sims 2 sprite problem

My Sims 2 has been successfully installed, no problems whatsoever about the game itself. But once in a while, my Sim's sprites just strech out of the screen, or sometimes, my Sim's heads float around without a body. In other times, specially when the character is outside, the character looses hair or has black things on his/her clothes. What can I do? I have Toshiba Satellite A215-S7437. Video Card is 128MB, RAM is 1.8Gb. I am currently trying to update video drivers, but in case it fails, please help me.