Can anyone diagnose this strange Firefox problem?

Factual Questions
1

I have a work laptop that I shuttle back and forth between the office and working at home over VPN. Work requires that I use IE for my browser, so I use Firefox for personal browsing. Lately (last month or so), Firefox has started crashing intermittently and fairly often–but only at home. Never at work.

I’ve tried upgrading Firefox to the latest version, downgrading it to an older version that I know worked fine…nothing seems to fix the problem. And it’s completely intermittent–sometimes I can go most of a day without a crash, and other times (like this morning) it crashes if I look at it funny. And this is with the same basic set of sites (I have a group of about 20 or so sites that I look at, all of them safe/legitimate (news, SDMB, a few well established WoW-related sites, etc.) and rarely go outside of that. There doesn’t seem to be any rhyme or reason about which pages make it crash.)

Any idea why the same installation of Firefox on the same computer would be completely stable on the company system but flaky on VPN? This is driving me crazy.

2

I got nothin’ for you, but lately I can’t VPN from home at all using Firefox. It says I’m missing an add-on. When I try to download the add-on it says it’s incompatible with Firefox 3.6.3. So I just use Explorer for VPN purposes at home now. Are the two issues related? I have no idea. (And can’t remember the add-on name at the moment.)

3

Speaking of add-ons do you have any installed? The add-ons you have installed are just as likely (if not more so) to be the cause.

4

IIRC Firefox will retain your cookies, temp files and history between installations, even if you downgrade.

Have you tried clearing your cache and possibly your cookies too? You don’t have to remove all cookies, you can go through them and delete them manually. But it might help to delete them all.

If you want to do it thoroughly, check out CCleaner.

5

Are you using ZoneAlarm, Firefox, and Vista together?

Apparently, there is a bug. I resolved it* by going with Comodo Firewall rather than ZoneAlarm.

*I think. I haven’t had much time to work with it.

6

It’s not clear: are you using IE at home with no problem? Just want to make sure it’s FF, not your home internet connection that’s at fault.

7

You can go even further and set up a new profile in Firefox. This will get around all the settings that may be screwed up.

But go ahead and try CCleaner first. I’ve never had it fix crashes, but I have had it fix hangups, as it will fix a bunch of Firefox’s files.

8

Thanks for all the suggestions. Let me answer some questions all at once:

  1. Yes, I have some addons installed, but not many. And if they were the problem, why would they be fine at work but not home?

  2. I’m not using Vista–this machine is running WinXP Professional.

  3. IE works fine both at home and at work.

I’ll try clearing the cache and the cookies and see if that helps.

9

I resolved my problem in post two by:

This was a URoam/XHost/Plugin file.

10

Why would Firefox itself work sporadically? Firefox add-ons have the ability to change pretty much any aspect of the program, so without knowing which ones you have installed it is almost impossible to rule them out.