Windows 7 Not Recognizing HDs

Your use of terminology is a little confusing.

Physical disks (actual hard drive units, in this case you say 3x 1TB Caviar blacks) must be partitioned and formatted in order to be used in a computer. This partition may extend to use all of the available space on one physical disk, or some smaller part of it. Thus, one physical disk has the potential to contain more than one disk partition. Depending on how you set these partitions up, they may be assigned a drive letter (this is the most common/popular method). These partitions, once created, formatted and assigned a drive letter, then appear in your OS, for example, in "my computer" in windows. In windows installations, the OS partition (the primary partition on which the operating system is installed) is ALWAYS "C:"

In your first post, it sounded like your setup was this:
;
Physical disk 0/1TB Caviar Black 01 = C: + D: + Z:

So in "my computer" you would have had these three drives appear as separate drives.

When you say that D: was a partition of C:, it sounds as if you may have attempted to partition your Physical disk that contained your C: partition. For reasons that I hope are more obvious to you now, this action would corrupt your windows install by pretty much destroying your C: partition.

If in fact you had three physical disks - that is to say 3 separate 1TB caviar black hard drives, then how was each drive partitioned because if the first physical disk was divided into 2 partitions, C: & D:, and Z: occupied an entirely separate physical disk, then that leaves an entire physical disk unaccounted for. OR if instead one physical disk was divided into 3 partitions (C:, D: & Z (which is what you've written) and only the C: partition is corrupted, then chkdsk may still recover your partition table, which will allow you access to your D: & Z: partitions - although you'll want to immediately back them up to a separate physical disk.

As good sense dictates, there is almost no use at all in backing up your system or data to the same physical disk, as it is disk failure that you are trying to protect yourself from.

Please explain again what your partition configuration was, with reference to the 3 physical disks that you listed in the original post. Also, please confirm that all three partitions (C:, D: & Z all existed at the same time, and that you did not partition your C: into two partitions, D: & Z:

That will make your question easier to answer.