Firefox profiles suddenly deleted and browser updated after reset

Hello,

After steam started acting funny I quickly rebooted the PC. Since the PC had been running for a few days lots of programs were running and I was too lazy to wait for them to shut down - so I simply reset the PC. Big mistake apparently.

Firefox, v. 3.6.25 was updated to 4.01 after the reboot and all my profiles were not visible anymore in the profile manager.

So I uninstalled 4.01 and reinstalled 3.6.25.

Here's where the "fun" starts: the old profiles are not recognized anymore in the profile manager even though they are still in AppData\Local\Mozilla\Firefox\Profiles.

I also tried copy/pasting the contents of a profile into a new profile. Still, nothing happens when I restart the browser, no bookmarks, no addons, no browsing history etc.

Finally, I thought that all of the profiles of this user might be corrupted, so I logged in on my admin account and started firefox there (also 3.6.25 btw). This one worked fine, though it obviously was ~7-8 months outdated - not a total loss though. So I copied this profile on a USB stick and again tried a) copying it into the appdata\local\mozilla\firefox\profiles folder and b) simply copying the contents into a new profile.

Again, nothing happens with the result that nothing is recognized. This is particularly odd since I know that the admin account firefox profile works fine on the admin account AND both firefox versions (admin and user account) are versions 3.6.25.

I've already googled quite a bit but couldn't find anything.
I'm using win 7 ultimate 64 bit if that is relevant.

Any advice/assistance would be greatly appreciated.

Tom

Used a month old image and manually backed up some other files. Everything works again.

Hey, um, what did you do to get an old image? Do a system restore from a month prior and then back up the profile files?

My profile folder is full of file-types that are unrecognized (bak, dat, json, rdf, sqlite).

I don't know how it happened or how to fix it.

Also have unrecognized applications in FF, in Options>Applications (mailto, webcal,etc).

Super weird, and annoying.