Video Hardware Acceleration

I have a MacBook Pro with a 2.4 GHz Intel Core i5 and 4 GB 13333 MHz DDR3 memory. It is running os x 10.7.5. Whenever I try to play Guild Wars 2 or The Sims Medieval, I get the following error:

"Video Hardware acceleration is currently disabled due to safe mode operation or a driver error. Please ensure you have a working OpenGL Hardware Renderer and try again."

I

All that I have done is uninstall and reinstall The Sims. I only know the basics about computers - I don't know how to go in and change code nor do I want to. I'm also wary about downloading unfamiliar programs off the internet and possibly destroying my computer. Does anyone have any advice about this issue? If there isn't an easy fix, I guess I'll just stop trying to play these games and hope anything else I may buy works.

Thanks in advance.