OK, I'm running Win7 7201 64-bit. I installed COD4 1.7 last night and when asked about installing DX9 I selected "No" since my Win7 has DX11 installed. When I try and start either single or multi-player I get an error dialog that reads: "The program can't start because d3dx9_34.dll is missing from your computer. Try reinstalling the program to fix this problem." I note on my old XP partition that d3dx9_34.dll is installed in C:\Windows\System32. I get the impression that I HAVE to install DX9 even though I already have DX11 installed ? Does this make sense ? Will installing DX9 cause any known conflicts with DX11 ? Is there a DX11 compatibility pack required or something ?