Z77-D3H installed Win 8, all is well, then won't boot after installing HDD

[zeusdog]

Z77-D3H mobo
i5 3330 processor
16 GB Patriot DDR3 1600 memory
128 GB Samusung 840 Pro SSD
Windows 8

Windows 8 installed and runs fine.  (Not that I'd call Win 8 fine - it's awful.  But that's another discussion.)

Then I added back in an old Seagate 128 GB SATA HDD.  Still runs fine. Starts, sleeps, wakes up, runs apps, etc.

The Problem:  Then I added back in an old Maxtor 320 GB SATA HDD.  Machine POSTs, briefly flashes a Windows logo, then restarts.  POSTs again, then displays the Windows logo with "Preparing Automatic Repair."  Stays at that screen; nothing further happens, even after an hour.

If I restart the system and go into UEFI BIOS, the Maxtor 320 GB drive is correctly recognized, but is not in the boot sequence.

If (in the UEFI BIOS), I configure the SATA channel as hot-pluggable, shut down, disconnect the Maxtor drive, then power up, Windows 8 starts fine.  I can then plug in the Maxtor drive and use it with no further problems.  I can put the machine to sleep and it wakes up fine.  The Maxtor HDD shows up properly in Disk Manager.  But if I shut down and power up again, then I'm right back to The Problem (as above).

The SSD is GPT.  Both HDDs are GPT, but one of them causes problems and the other doesn't.  Other than size and manufacturer, the only apparent difference between the two HDDs is that the Maxtor has two partitions on it (both NTFS).  The first is empty; the second has data directories.  None of the partitions on either HDD has an OS on it.

Any ideas? 

[zeusdog]

The 320 GB Maxtor HDD had two partitions (and hence two logical volumes) on it.  The first had an old WinXP OS on it.  The second had nothing but data - project files, photos, music, etc.

When I first tried to install Win 8, the machine would try (and fail) to boot XP instead, so I deleted that volume (but not the partition) on the Maxtor disk.  Apparently, that left the empty partition still designated as "active."  Once I deleted the now-unused partition (where XP had been), the machine booted without problem.

A remaining inconvenience was that it is not possible to "extend" a partition to unallocated space before it (space to the left of it in Disk Manager).  So I had to back up everything on that volume, delete the volume and the partition, then create a new simple volume in Disk Manager.  Now I'll just copy everything back to that volume.

Problem solved.