Hi Mel, i've had a quick look at your post, and on first inspection, i must ask you a few questions, first of all, when you installed the graphics driver, was it from the disc or did you download them (I must point you to this driver
>>>here<<< for your Graphics card). secondly, the DirectX diagnostic info you posted is not very useful because it doesnt show your GPU info for your new card, of which will not install.
If you can, don't disable the onboard graphics card when you install the drivers for the new card, just leave it enabled. My main speculation on why it has went wrong could be a number of reasons, if you installed the GPU off the disc, then the driver maybe the 32bit version, where you need the 64bit version for it to operate.