I encountered the error “Unable to initialize 3D output. Please verify that you have installed DirectX 9 and an updated video driver. "
New installation of W7, DX9 and GW2.
Solved by turning GPU scaling ON in AMD Radeon Settings
guide: http://support.amd.com/en-us/kb-articles/Pages/UnableToSetGPUScaling.aspx
Since I have found no solution on the internet, I add it here for future use. Hope it helps.
