|DirectX 9C, which is included in SP2, is backwards compatible with DirectX 8. |
Not only do you need the software support for a certain version of DirectX, you also need the hardware for it. Do you have a graphics card that supports DirectX 8 or higher?
The amount of RAM you have stated (1.43GB) implies you have some version of integrated graphics.
Mobo: Asus P7P55D LE
OS: Microsoft Windows 7 Professional OEM
CPU: Core i5 750 @ 2.67 GHz
RAM: Corsair Dominator DHX+ DDR3 1600MH 4GB
GPU: Sapphire 4870 D