Firefox not closing

WinXP Pro SP2 - Firefox 3.0.10
Lately, when I close FF, the program window closes as usual, but if I check the Task Manager, the firefox.exe file remains running. I realize that it has things to do right after being shut down, like housekeeping or whatever, and it usually closes completely shortly thereafter. But occasionally (like this morning when I shut down before going to work) it stayed open in the Task Manager for over 5 minutes and I manually ended the process then powered down. It's not a HUGE deal; when I end the process, the next time I start Firefox, I get the "your last session ended unexpectedly" message. So it's not a big deal, I'm just hoping it's not a sign of a bigger, deeper problem, or of some impending disaster. Any thoughts or suggestions or comments are welcome.
:-D

[dlb]

 

Thanks DomLuc.... lots of info in those links. I'll take slow walk through the stuff tonight and tomorrow and see if something there clears it up. If this was a consistent issue, it might be easier to pinpoint, but it only happens maybe 1 in 4 or 5 times :confused

 

I went through a bunch of stuff in the links provided by DomLuc, and couldn't find anything amiss with FF. But, as I suspected, it was a 'problem' with FFs 'housekeeping', namely the cookies and history. As soon as I changed the cookie settings to 'clear when I close Firefox', and disabled 'Remember what I downloaded' and disabled 'Keep my history', FF now closes normally and completely. I'm going to mess with these settings a bit more, but I'm pretty sure it's the cookie setting causing the lag in FF completely shutting down. If I come up with something new and/or interesting, I'll post it.

[dlb]

EDIT- since I made the changes posted above, FF seems to open faster and just seems 'snappier' somehow, but it could be my imagination, or the four ice-cold Sierra Nevada Porter's I've comsumed :drink LOL

 

:cry I spoke too soon FF worked OK after I made the changes I listed above, but it's now back to its same old not-closing-completely self. There was a Java update requesting installation in the system tray and I'd been ignoring it, so maybe that's the issue. I did finally install it this morning, so we'll see. I'll have to go thru those links posted my DomLuc again to see if I missed something....