How do i turn down graphics acceleration?

Hi, i have an Nvidia GeForce GT220 1GB Graphics card. I was wondering how to turn down the hardware acceleration because i want to play a game which requires it turning down?
I have gone into display settings but the 'change settings' button is grayed out. HELP!

Turned down how? SLowed down? Turned off? features disabled?

Anyway it sort of looks like you might not have the real nvidia drivers installed looking at that dialog. There should be a tab there with the nvidia logo and the name of your card. Try right clicking your desktop and there should be a "NVIDIA control panel" item there. If not the go install the latest drivers from nvidias site.

But I'm still not sure that you will be able to do what you want. Which.. I'm not sure what that is