I'm still working the problem here. Was able to get XP Pro x64 to boot when AHCI was selected in the BIOS but not XP Pro or Win7 32- or 64-bit. Word on the MSFN forum is AHCI must be selected in the BIOS during the install of Win7 to get the drivers loaded. Have not checked this as I have SATA CD/DVD drives connected and if I switch the BIOS to AHCI they no longer appear as boot devices; that's a different problem I'll have to pursue.
I do not have RAID selected in the BIOS and I do not plan on trying that option because of the re-formatting issue.
Ran HWIDS from each XP Pro in IDE mode but the RAID Device was/is the same for both. Will have to try it from within XP Pro x64 next time I boot it using AHCI.
When I was troubleshooting to try to determine any connection between why one system would boot and not the other and comparing the two .REG files I found; one posted on MSFN and the other at PC Perspectives forum, I did notice there were two driver listings in the registry of my XP Pro x64 system and minor differences between the .REG files.
I am also considering making a new .REG file that is a combination of the two .REG files I've been using and the listings/entries I did find in the registry themselves. My experience tells me that importing this information into the registry will not cause either XP Pro or XP Pro x64 to not boot if in IDE mode and to either give my a BSOD as I had previously when I switched to AHCI or to actually boot. Again, experience dictates that registry listings will be ignored if the item listed is not to be found and that listing just becomes redundant.
Obviously I'll create a restore point as a safety measure.
Monday Night Football kickoff and dinner time is fast approaching here in California so it will probably be tomorrow before I have any more information or answers.
