Hi Arthurb,
I'm not going to teach you because my knoledge is very limited. I'm going only to tell you what I would have done if I were in your shoes.
I reviewed all the posts in your subject, I would have decided to put the "Partition Magic" diskets to wipe totally both hard disks again and reformat them to "NTFS". Then make the partitions that I want. After that I install Windows XP and that'll be all.
I know It'll seem to you too simple or even crazy because you don't like to erase again after installing many other programs. Well me, to avoid head breaking with unknown problems that manifest themselves from time to time and in many ways here and there, I would have done it.
Why I'm telling you that?
I think, you well know that if you like to install multiboot system you must install the older Windows first and after that the more recent. I understand that you want not to make multiboot but only one.
Because you tried to install different Windows versions, probably everyone of them left some traces (elements) on the hard disk. And non of them was installed completely as it should be. Sometimes you try to install the more recent first, some other times the older first. The elements from each probably got some conflicts or didn't fit to be with the others on the same computer. So, they were never wiped totally by the alternation of different Windows installations.(It happened as if you were making multiboot not respecting the order that the older one must be first.) That's why I think it's better to wipe bothe disks totally and to start again by using them like version ones.
So, instead of going and searching from site to site for drivers and other elements, you have the Windows XP which will install by itself everything you will need.
Please Adept, Lobo Sandra and others, don't lough at me because of my analyse. I well know that I am limited in computer matters. But anyway I just wanted to express myself.