PROBLEM RESOLVED
I found the problem (by accident).
When I was in a Windows XP session, I decided to do a Norton Disk Doctor
check on the drives (C: and D

. With the D: drive being the one in question
here!
I couldn't perform this check, until I disabled Norton's GoBack. Well, I
haven't "enabled" Norton GoBack yet. I plugged in the removeable SATA HDD
rack containing Windows Vista Ultimate and booted up. I wanted to find
something on the C: drive, so I went into Windows Explorer. Lo and
behold....the D: drive is now showing!
Why? I am assuming that the Norton GoBack has specific descriptors that
only it (GoBack app) would recognize --- effectively hiding this drive from
Windows Vista. I think that if I installed Norton GoBack here (in Vista) and
had it set for both drives (C: and D

that I WOULD be able to see it here.
Anyways, thanks for the help, everybody.
"Albert Trudeau" wrote:
> I'm still looking for a solution for my problem.
>
> I have installed a 'secondary' SATA HDD and though you can see it in the
> "Disk Management" window (Computer Management Console), there isn't a drive
> letter assigned, nor can I assign a drive letter.
>
> The 'Volume' column shows the drive (without an assigned drive letter)
> The 'Layout' column shows "Simple" (just like the C: drive)
> The 'Type' is "Basic" (just like the C: drive)
> The 'File System' is blank (whereas the C: drive shows NTFS)
> The 'Status' is "Healthy, (Active, Primary Partition); (whereas the C: drive
> is listed as "Healthy (System, Boot, Page File, Active, Crash Dump, Primary
> Partition))
>
> The only anomaly listed above is under the "%Free" column; this is at 100%
> -- which is, of course, false. This is my Backup D: drive that is listed in
> Windows XP Professional, etc.
>
> The 'pop-up' menu will only list 'Delete Volume' and 'Help'. All other
> selections are unavailable (ghosted out).
>
> This 'glitch' is preventing me from running Vista full-time. I would love
> to hear a solution as soon as possible. Thank you.
>
> Albert Trudeau