Hi Terry,
If you locate your original Firefox profile, usually in C:\Documents and Settings\[username]\Application Data\Mozilla\Firefox\Profiles\xxxxxxxx.default, you should either be able to do one of two things:
1. Copy the entire [xxxxxxxx.default] folder to the same directory on the new machine, then switch to the new (old) profile in Firefox.
or...
2. Copy the contents of the [xxxxxxxx.default] folder, and over-write all the files in the newly created profile on the new machine. It's the [prefs.js] file which is the critical one, as this contains all the settings, but if you also have add-ons, and extensions, it's best to copy the entire folder contents.
Whichever method you choose, I would strongly advise to keep a back up of your original Firefox profile folder.
Now, there's a caveat to all this, and that is, I can't promise that there won't be any compatibility issues, when moving all the files to Vista, and from what I can gather, from reading
these release notes, there are still a few niggles with Firefox and Vista.
Best of luck!