Ah, I miss read the required you have, I thought it was you have required.
The only thing I can see is that it wants you to have a 6600GT or x1600 or better. It might detect your low end onboard as weaker. If it supports SM4 and you need SM3, they are backwards compatible so it should work. If you look at your first post it says you don't meet the requirement as soon as it mentions supported chips.
Fact remains you need a video card. Check your documentation or crack the case and look. (might void your warranty.) Only way to play.