So now I’m not quite sure if you have already followed the steps you yourself quoted in your previous post. And if you have, if you’re now able to invoke the blue screen by using the Ctrl + 2x ScrollLock key trick (make sure to reboot the system after making the registry change).

I'm not questioning you at all (although I'm about to ask a question, so I suppose I am really! ) but if this started when the 2nd harddrive was put in, and I can temporarily stop the problem by disabling it, isn't the problem for Avast being caused by something I've done with the HDD? Please accept my apologies in advance if you're all now holding your heads in disbelief at the stupidity of this question!

With all respect, I’m reluctant to make any conclusions until I actually see the dump.

Cheers
Vlk