My games and Windows Vista Business

[GLH]

Now i tried to play these games (Overlord, Battlefield 2, S.T.A.L.K.E.R., Ghost Recon Adv. Warfighter 2) and i have the same problem i've described in this thread (post #1 & #3) with each game.
Also the original discs (without crack) brings me this error, but it think it takes a few more minutes until the pc shut down.

First i was thinking that DirectX10 contains all the components of DirectX9, so i haven't installed DX9. But now i installed DirectX9 and the problem still occurs.

Does anyone have had the same problem and can tell me a solution?
Or does anyone have a clue about this?

My (new) system-specs:
AsRock 4CoreDual-VSTA (Mainboard).... using the drivers that came with WinVistaBusiness
2x 1GByte Corsair DDR2-RAM PC2-5300 667Mhz
Intel Pentium D 820 (DualCore 2,8 GHz)
nVidia GeForce 7800 GTX (Leadtek).... using original nVidia driver v158.24
Realtek onBoard Sound 7.1.... using Realtek HD-Audio driver v1.70


Is it because of the DualCore processor?
Do i need a programm to set a game to use only one core? (I heard there is a tool/driver for AMDs X2 processors)
Should i install the original mainboard drivers? They are older than WinVistaBusiness....

EDIT: The Intel DualCore Patch for Vista (KB936357) is already installed.