...you've got plenty of physical memory. Does the crash happen everytime you play, always at the same point, or is it random? Do you know what the error message is exactly?
How long am I willing to put into this? Well, I've put about 500+ hours in to get this far, so as long as it takes basically!
Put it this way, if you were talking about producing something of the size and depth of MM6-8 then you're talking about years of work rather than months.
Anyone who wants to help, in any way, will be most welcome. I'll be posting more info about getting a group together to produce a game after the demo has had a bit more time to circulate...