Latest details. I have replaced the video card as I have mentioned before but same thing. I have loaded the ASUS PC Probe program to check CPU, MB temp and fan speed with an interesting result. The sample was set to every 2 secs and I ended up with the CPU temp 'cycling' from 33 - 42 - 51 - 60 and back to 33 again also a similar pattern with the MB temp 36 - 45 - 54 - 63 and back again. The fan speed also cycled from around 6000 up to a top of around 9000 but was reach max on a different cycle i.e. not linked to either CPU or MB temps. I reloaded the PC Probe program but got the same results.
I have also run with only one stick of 1GB ram at a time with the same result of the black screen of death, so it is not that. I even tried a bigger power supply and checked the PC Probe yep same cycling temps again. The black screen also made its appearance with the bigger power supply. It has also occured on other games eg FS2004.
So my next options are probably to reload Win XP, I also have another CPU on the way AMD 64 3200+ socket 754 @2.2Ghz. I guess if this doesn't fix it then it's motherboard time?
Any thoughts?