Differences between lrcat and lrdb files with new OS and LR 2?

Question

So I just refurbished my machine by wipping my drives that contain the
operating system (Win XP Pro) and other program files. I did regular backups
of all including the various settings for lightroom and everything else I
could find outside of the backup that LR would do on it's own. Previously,
before this refurbishment, I was using LR 1.4 and just did install LR 2.1. I
hadn't upgraded any of my LR databases as I created a temporary picture
database on another drive just to test drive 2.1. So essentially, I had both
LR 1.4 and LR 2.1 install simutaniously. Didn't have any issues either, but
again, just checking out 2.1 prior to abandoning 1.4. Anyhow, in my new
setup I was just going to go with LR 2.1. Realizing that my catalog files
(.lrcat) would prompt to be updated, I am thinking I am fine. But since
Adobe's LR likes to place files all over the place from 'program files' to
'application data' to 'my pictures', I ended up with what "seems" to be some
duplicates and/or am a bit confused as I am not sure what goes where. I
mean, I think I have it all down as I backed up some items such as the lrdb
files and then brought in some stuff I had backed up before this
refurbishment. All seems fine, but I would rather aviod issues in the
future. So could someone tell me what goes where and their file name(s) and
extensions? And when doing this, what is the difference between the lrcat
and the lrdb files? Seems LR 2.1 doesn't contain or create lrdb files. And
lastly, where are my preview files? When I set the lrcat files to point to
my old setup/stuff, the pictures just take a very quick moment before they
are clear and whatnot. Is it best just to recreate? And lastly, is there a
way for me to test and check to make sure I moved the right things into the
right places and that all is working as it should with the proper files? As
an example, all the folders/files that were here "C:\Documents and
Settings\Mark G\Application Data\Adobe\Lightroom" I just copied and wrote
over from my backup prior to the refurbishment and things such as my custom
and downloaded web galleries look fine. Any other thoughts? Sorry for the
long read and thanks for any and all help/input you all can provide.

Answer 1

>And when doing this, what is the difference between the lrcat
>and the lrdb files?
In versions up to and including V1.0, Lightroom catalog files were .lrdb (for Lightroom database). So, if you have already been working with V1.4 you can get rid of any .lrdb files that you may still have.
As regards file locations you could do searches for the following file types:
.lrcat (catalogues and backed-up catalogues)
.lrtemplate (templates and presets)
.agprefs (your preferences file)
previews.ldata (in same folder and with same name as your catalogs)
Lightroom allows you to choose where your catalogs (and associated previews) are stored. It also allows you to specify where Lightroom backs up your catalogs.
Templates and presets are stored in C:\Documents and Settings\YourUsername\Application Data\Adobe\Lightroom
This message gives you a summary of files and it references a Tech Note: http://www.adobeforums.com/webx/.3bc3994c