Found another XP install 'gotcha'. One of my antivirus software packages wreaked havoc on my big box. I'm thinking is was 'SpyBot - Search & Destroy', but I can't be sure. In any event, XP's PC Health function and the REGEDIT editor took a hit. I was able partially reinstall PC Health but there are a few problems left over. While the system does run, and the all important games side of it functions okay, there are still a few things going on that aren't up to par.
My solution was to reinstall and get on with life. So, I booted with my XP install CD and made it up to "Starting Windows', then got the BSOD:
***STOP: 0x0000007B (0xF78D2524, 0xc000034, 0x00000000, 0x00000000)
What is key here is 0x0000007B. This means XP is possibly not detecting the HD. There are reams written on this failure, and if by chance you get hit by it, things can become frustrating real quick. It should be noted that my motherboard, an Asus Sabertooth FX990, was initially setup as ACHI, not IDE. When I decided to add XP on a separate WD 600 GB Velociraptor, the XP install went well without having to fiddle with the UFEI/BIOS settings; i.e., ACHI or IDE. Both, W10 on a 500 GB SSD and XP on a 600 GB IDE, functioned perfectly as ACHI. So what changed when attempting to reinstall XP? I figure it must be with the way the BIOS treats a storage device on the 'initial' install. It looks like you would have to FDISK the target HD in order to get back to square 1, or simply go into the BIOS and change the SATA setting to IDE. Long story short, that worked. I'm thinking XP's handling of ACHI may not be up to today's standards. Hope this helps someone down the line.