Hello Mark,

Sorry for the delayed reply but I got a lot going on in my life, not to sound like a drama king but that is really the case...anyhow.

After reading your long post and trying to make sense of it all, I decided that it'd be better to permanently leave this forum, sell my earthly belongings and relocate to Tibet to become a monk.....lol....kidding (kinda)....

Ok, seriously though, first of, the most common cause of the problem you just describe (regardless of how what proper method you use) is either a corrupt file in Windows or an incorrect Power (APM) related settings in BIOS.

When you initiate the shutdown process in Windows, the Operating System goes through its preconfigured instruction sets to close applications, shutdown services, etc. the final command sent utilizes the kill power feature of the BIOS, which causes BIOS to power off via the PW/PW_ON cable that is connected from the front of the case to the motherboard (this is commonly the cause with ATX cases of course).

In a rough way the above is the process, what could be the culprit? The Os file(s) that handles that power off commands (corrupted) or power related settings either in Windows or in the BIOS in related to Power options.

What you need to figure out (you might have already answered this in your last post but I might have missed it):
~ What was changed in this system prior to this issue?

~ Changed Hard Drive? Is the new Hard Drive a higher capacity than the previous one? If so, is it supported by BIOS and/or the OS (more importantly BIOS)? IF not certian, have I checked the mobo manufacturer's we site to see if there is a newer BIOS version? (If yes, read the version details to see what got fixed, if nothing about supported HD is listed, read general product spec sheet)

~ Re-installed OS fresh or using what was already installed possibly in another system?

~ Did I work in the case? If yes, could I have possibly unplugged or loosened up any of the cable connecting from the case power switch to motherboard?

~ Did I feel brave and messed around with the BIOS settings? If so, have I tried resetting the settings?

Remember, each motherboard has a different reference for SATA drives. Mobos often sees SATA drives just like SCSI drives, in plain English, they do not detect them! Only IDE Hard Drives and CD/DVD-ROM drives that has the ATA-33 connection will be detected in BIOS. So, your SATA drive may not be detected, as long as the OS sees it once the the SATA drivers are installed during OS installation, things should work fine when booting or shutting down the system.
I am not 100% clear on how you have the drives connected. I believe you have 2 PCs, but not sure which PC is having the problem, regardless which drives do you have connected in the troubled PC? and which one is the boot drive?
OR
Are you and your wife sharing the same PC and just switching between hard drives in the same PC by changing the BIOS settings (which is really an odd way and can't say a proper way either)?

But to start you off with common, simple things to check for: on the troubled system START > RUN > powercfg.cpl > OK > check to make sure all settings are correct.
Then during reboot, go into BIOS settings and check the settings on the Power Configuration section.