Location of profile -- need to understand what happened here

Question

I just resolved a data recovery crisis with my bookmarks. Although the crisis is over, I don't understand an important aspect of what happened, and I need to resolve this to be entirely confident of my data's safety.
Last week my computer contracted a virus. My attempts to remove it have been unsuccessful so far, so I fell back to an alternate version of Windows XP that I keep on my computer for that purpose. I have a separate data disk and configure all of my applications to store their data there, so this should be a nearly complete workaround -- all I lack is new software that I've installed since I created the backup partition.
As I checked out the system after booting, I looked at my Firefox bookmark file and was flabbergasted to find that its time stamp was over three years old.
I did some research and discovered that when Firefox went to version 3 it replaced the bookmark file with a database stored in a "profile" in the Application Data directory. I wasn't aware of that, so I never reconfigured Firefox to move the profile to my data disk.
This looked very, very bad. It looked like I'd said goodbye to all the bookmarks I've collected since I created the backup system until I got my infected system working again.
To make the best of it, I deleted the useless bookmark file and moved the Firefox profile from my system disk to my data disk, where it should have been all along.
Then I started Firefox (this system is running version 4) and found that all of my bookmarks were there, right up to the one that I added yesterday with instructions for removing the particular virus I'm dealing with.
How did it do that?
I first thought there must be another profile on the data disk, but I searched the whole disk for one of the file names in the profile, and found only the one I had just created. Later I realized that even if there were another profile, that wouldn't explain what had happened. Firefox is now using the one that I just created -- I checked the timestamps to confirm that they were being updated -- and I copied it from a system drive in a partition that hasn't been used for months. I'm delighted to have all of my bookmarks, but they seem to arrived where I need them by magic. What could have happened here?

Answer 1

auscompgeek, I appreciate your effort to help. Either your response doesn't address the question, or I don't understand it.
Here's how it looks to me: places.sqlite is part of the profile, i.e., it is one of the files in the directory that contains the profile. I've explained what happened to that directory. The fact that the bookmarks are stored in this particular file is true, but doesn't explain anything.
I searched my data disk for this file on the chance that there was a stray copy of it somewhere, not in a complete profile directory that contained the file I originally searched for. I found it only in the new profile that I created after discovering the problem.
So this issue still appears to be unresolved.