As suggested, I just tried out the Recovery Environment as part of my evaluation of ShadowProtect. I booted to it, made sure that I could access all my drives, and did a Full Backup of my system volume and verified it (can't believe how quick this was! How does it do that?).  Then I tried Exploring it, first mounting it as a drive letter and then as a mount point.

Mostly everything worked as it should, but not quite everything.

1) When I first got into the Recovery Environment and looked at my Disk Map, none of the letters for my drives matched how I have them assigned on my system.  For example, I have three internal drives: my primary drive has a C partition (system and applications) and a D partition (documents and data); my secondary drive is E (single partition), and the third is I, but in the Recovery Environment these volumes were C and I (on the primary drive), F, and D, respectively.  Same with my two eSATA drives, my Firewire 800 drive, and my USB drive - all appeared to have been randomly assigned drive letters.  Is this how it should work?

2) I was able to mount my backup image fine as a drive letter and to explore the mounted image.  But when I attempted to mount it as a mount point (either to the default location or to another location), I got the following error:

"SPExplorer.exe Application Error.  The instructions at 0x7c283b40 referenced memory at 0x00000050.  The memoery could not be read. Click OK to terminate the program."

Any ideas what this might mean? Should I be worried about it if I'm able to mount an image as a drive letter?

I didn't attempt to actually restore my system volume.  But I do have some questions about the restore process.  I've read through some forum answers, which were helpful, but I'm still uncertain about this, and I'd like to understand before the situation arises in which I need to do it!

3) If I'm restoring my system to the same drive - ie, the reason for the install is something like a software issue rather than a hard drive failure - I'm assuming I can just install directly over my current C volume, which is a partition of my primary drive, and as long as I don't choose any of the context menu options to delete or repartition, SP will know to use the existing space and will not touch the other partition on that hard drive. So I'll end up with a primary drive that looks exactly as it did before the restore - in my case, with C (system) and D partitions, the same size as they were before.  Is this correct?

4) But if my hard drive fails and I'm restoring to a new hard drive (in the same computer, so no HIR for the moment) - how can I set it up to partition that drive the way I want?  Let's say my current C volume is a 100Gb partition, but only 30 Gb of it is full, and I'm using SP without the option that backs up free space sectors, so only the used 30Gb are being backed up.  And my D volume is a 900Gb partition on the same drive.  And I want to restore to exactly the same size drive, partitioned exctly the same way.  How do I do this?

I read in one of the forum answers that in this situation I should select the system volume, which I'm restoring, then right click on the unallocated space of the new disk, and select create exact fit (or exact size?) partition at the beginning of the disk.  But what's worrying me is what is meant by "exact fit partition" - if I wasn't backing up the free sectors, does that mean 30Gb, which is the size of the backed up image (the used space on the partition), or 100Gb, which was the total size of the partition?  Does exact fit include the free space, even if I didn't select the free space option in my backup?  Will that only create the C partition and leave the rest of the drive unallocated, to be partitioned either when I restore the D volume or manually by me, or will it create both partitions to mirror the entire drive?

I know this all sounds fussy - but I accidentally did a system restore once, years ago, using my computer manufacturer's Acronis system restore disk, to an external drive rather than my C drive, and wiped out all the data on that drive - to this day I don't know how I did it; I can't recall any options for selecting where the restore should go! - and so I want to be quite sure I understand the procedure.

Thanks!

1) The Vista or XP on CD can have different drive letter assignments because the original machine has those in its registry which the recovery environment doesn't scan or use. It is not a problem for most if not all cases.

2) It means Nate forgot to handle it correctly in the program code. ;-) In other works, looks to be a programming error.

3) Yes

4) You have to create the target partition anyway if it does not exist or is too small. The rest will be unallocated until you restore D: as well. The restore process is one partition at a time, there will not be your full master boot record with all partitions fall out of thin air. Partition size is what matters, not unused free space. If source partition was 100 GB you have that size again (unless using 3.3 and shrink ray).

There is no margin of error with computers. The manual could be of some help maybe. 

A2) The mount itself, to a mount-point, succeeds, the problem is in SPExplorer.exe which is only used in the recovery environment as a file browser - it crashes when launched to view a mount point directory.  I'll ask the guy who is responsible for SPExplorer.exe to look into this.  Thanks for the heads up!