3 things stand out to be from your dxdiag.

Your video chipset might not be (probably isn't) up to the job (as noted above)
Your running directx 10 - C4 was designed for 9.0c
You make no mention of trying compatibility mode

When c4 is loaded try going to the shortcut and selecting properties. Choose XP Service Pack 2 compatibility mode.

It isn't a problem with that apparent "power" of a machine that causes the problems as much as Vista's issues with backward compatibility. Although on low detail I can (just) run C4 on my Eee PC 701 which is a far far worse spec than your machine. (I wouldn't recommend this to anyone, I just fancied the laugh trying to get it working)