Today's update...
To cut a long story short, I disconnected 'everything' from the MB, removed power cord & battery and shorted
cmos jumper and had a cup of tea.
Coming back refreshed I connected only 8 & 24 pin power, an old graphics card and 1GB trusty
RAM and it booted fine without long pauses - as far as it would without mouse, keyboard and hard disks.
One by one I attached things and it booted perfectly every time, I'm back into Windows now and even have 2GB of my Crucial's in.
Whether this will last remains to be seen but I'd say it was either the cup of tea or the fact that I cleared
cmos without the graphics card in - and haven't replaced it since.
It would be interesting to see if my original graphics card would work in the slot where the present working card is, that would hopefully tell me if the card is at fault or the slot itself - hope it's the slot because I stand to lose an EVGA 8800 Ultra water-cooled.
As far as my Crucial 8500 Tracers go, the minimum I can get one stick to boot at is 1.9v, 2 sticks at the same voltage just won't go (C1 error) - so much for booting at 1.8v Clunk.
So tomorrow will be spent playing with water and electronics.
At least I feel like I'm getting somewhere now.