Open Question: windows 7 cursor spazzing out?

im having a hard time controlling my cursor on my windows 7 computer i had cursor mania but i got rid of that and it still does it is there anything else it could be i have the sims 2 double deluxe some pictures,videos,and my favorites what could it be im afraid to tell my dad because this is a new computer i got for christmas but my sister who is 9 already broke hers what should i do how can i fix it will i have to tell my dad please help its really annoying and embarrassing when friends are over