Ok, after looking around the net I found the error message in full: "Ddhelp Caused an Invalid Page Fault in Module Unknown"
I have a couple of ideas for you to try.
A) Update your motherboard AGP driver to the latest version. If you're not sure what to look for reply with your motherboard's name and model and we'll help you out.
B) First, go to Add/Remove programs to uninstall any Nvidia drivers there. Then go to update your display adapter driver as normal, except override any automatic search by choosing "Install from a list or specific location" and then "Don't search. I will choose a driver to install." Install the Standard VGA driver. Reboot. Now install your latest nvidia driver.
It appears that the two major causes of this error (other than a faulty DirectX installation) are an old motherboard AGP driver causing a problem with DirectX 8.1 or a display adapter driver upgrade over an existing display adapter driver that messes up.
Try these out and let us know!