Firefox 3 choking on cookies (solution)

I upgraded both my laptop and then, cautiously, my main pc to Firefox 3.
Aside from a few extensions where keyboard shortcuts conflict in the new versions, and needing to reinstall a few fav extensions, the upgrade was more or less trouble free. Happy me, happy browser, the 'awesome bar' in FF3 is pretty neat (not sure it deserves 100% awesome status but it is really dang useful once you get past it being in-your-face annoying).  Happy everythingFox... and then... I realized I was being forgotten.

No longer would my iGoogle page greet me full of distraction and headlines when i launched a new FF session. No more full thread view on the first click when going to Experts Exchange. No more 'remember me' function. ... but so strange, the laptop still remembered everything. Same FF, mostly same extensions, and no "TorButton" (google it to see the known cookies issues) to cause the problem. The more it went on the more annoyed I got.

Picking at a solution in between long sessions of work and annoyance, I found lots of people having the same problem and very few ideas how to fix it.  The prevailing suggestion seemed to be "create a new FF profile" , but with my confidence in the upgrade flagging a little, i didnt want to mess with anything that is actually working (which is pretty much everything else in FF3).

And then... tonight... on page 4 of 6 in a long Mozilla forums thread, I found the golden nugget. You need to delete a file called "cookies.sqlite" that is in your firefox profiles folder (hence why making a new profile also fixes the problem)

Here is the solution :

Go to 
C:\Users\<your username>\AppData\Roaming\Mozilla\Firefox\Profiles

On my setup there was just one profile, and inside that, I deleted a file called "cookies.sqlite".

Apparently the file had gotten corrupted somehow, and session information was not being saved correctly.
Deleting the file (with Firefox closed) caused a reset, and instantly  I can tell things are a-ok.

The thread where i found the fix
( http://forums.mozillazine.org/viewtopic.php?f=38&t=675175&st=0&sk=t&sd=a&start=45 )

said to also delete cookies.txt

quote: "Note that cookies.txt is not used in FF3, but if you have one leftover from the upgrade, delete it too"