You can install a newer Firefox on the 2000 laptop, you just will have to ignore an warnings about out of date flash. I would use the Extended Support Release (ESR) of Firefox, since Windows 2000 will be dropped from support with Firefox 13. (http://www.mozilla.org/en-US/firefox/organizations/ for the ESR)

(http://weblogs.mozillazine.org/asa/archives/2012/01/end_of_firefox_win2k.html for the end of support)

As for transferring your profile, yes, you can simply move the profile over to the new machine. Backing up your information includes step by step information for transferring your profile.

Thanks for the information but while I'll try your suggestions they don't really answer my questions. First there's a question of confidence: - the laptop is Win 7 NOT 2000 - in Win 2K you can't just copy a file to a CD, you have to use another program (I use Burning Studio). This implies that whoever wrote the "Backing up..." hasn't really tried it. - Flash doesn't just give a warning: despite the constant nagging the new versions won't install. Same goes for Zone Alarm and AVG. Even VLC lets you d/l the new version and then just gives execution errors. Buried deep in one of their forums is a reply to a query that says effectively "Oh, yeah and we no longer support Win2K." VLC and the Tax preparation software (same problem) are effective driving my change far more than FF.

ESR would be just a temporary solution. Within a couple of months I'll upgrade the desktop to Windows 7 although there's a question of drivers. I might have to replace the motherboard (yikes! More expense and effort!)

The description of backing up doesn't specifically say "The profile files in Firefox are identical in FF V3.x and V11". I suppose I'll find out when I try it <g>. Nor, apart from "not just bookmarks", does it say what's included in profiles, particularly auto-completion of forms. Nor is there any mention of add-ons.

you don't have to put your old profile on a CD, you can use a Flash Drive if your computer has a USB port (or other form of media supported by both computers). And yes, the profile from 3.6 to 11 is fine to just copy and paste, Firefox will update any files it needs to as it goes along. If you read Recovering important data from an old profile, it gives the specific information that is included in each profile (if you want to just move a few things over, this article tells you which files to move).

but basically your profile contains everything from Firefox settings to bookmarks to auto complete entries to saved passwords.

Not quite sure what "Solved" means but I used your suggestions and had no problems at all. I now have a properly-running and even properly configured FF 11 on my laptop. Thanks.