I have an Acer Aspire.intel core i3-380M, 15.6 HD LED LCD, 4 BG DDR3 Memory, 500 GB HDD, and it's Windows 7. I don't know much about computers but I have invested a lot of money in these games and I REALLY need someone's help on why this is happening!!

I'm guessing your system can't handle it... maybe your graphics card isn't good enough.

Go here and run the program for Sims 3 and see what the results are.

Can You RUN It | Can I run that game | Game system requirements (http://www.systemrequirementslab.com/)