Thank you for your response.
The external capture device is a Blackmagic Intesity Shuttle, which, incidently, decided to work with Powerdirector once recently after my post. However if I can't use this device reliably with Powerdirector I don't really care because I can use it with another program anyway. It's just that capturing anything from inside Powerdirector is very touch-and-go.
I'm interested as to why my dxdiag results do not show up my nvidia GeForce GTX 670M graphics card, which is only one or two driver release behind. As for the Intel Graphics, attempts to update the driver in device manager always result in "the driver is up to date" (which apparently it isn't, is there another way to update it? And I run Powerdirector with my nvidia card anyway so I'm not sure if I need it updated).
I'm quite sure it's something specific to Powerdirector, as other programs work fine. And I very much hope all the physical connections in my computer are good because it's a laptop and therefore is not very easy to service.
I looked up what the "APC_INDEX_MISMATCH" means and I believe it's something to do with drivers running tasks incorrectly or incorrectly implemented drivers, something like that. In which case it would be Powerdirector, since my capture devices (webcams, the Blackmagic one, etc) work in other programs, wouldn't it?