On Wed, 6 Jul 2011 07:47:50 -0700 (PDT), Robert Macy
wrote:

I have an OS on an ailing HD.

Make and model? Is the HD failing with bad sectors, or is the data or
filesystem trashed?

Some key pieces of the initial
installations are missing -- sloppy storage and record keeping. For
archive functionality would like to be able to run the PC from time to
time. The idea is that while HD is working copy it quick.

Is there any free software that will take an image of a relatively
small HD (20GB, I think), place it in a region of a larger HD (say,
40GB), then later move the saved 'image' back onto the proper sections
of a similarly sized HD?

I use Acronis True Image Home 2011 for imaging.
http://www.acronis.com/backup-recovery/
The catch is that it needs a CD or USB flash drive to boot. This
sounds like an old machine that might not have these. For those, I
remove the drive, attach a USB to IDE adapter cable, and do the backup
on a different machine. It is also important to check the setting
that has it ignore bad sectors or this is likely to take a long time.

There are also free image backup programs, but I don't use them.
http://www.clonezilla.org
http://www.partimage.org

Another program I use to recover data from a trashed or failing drive
is:
http://www.restorer2000.com

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558