See: Upgrading from Firefox 1 Upgrading to Firefox 3.6 --- I would advice you to create a new profile for Firefox 3.6.3 to remove all leftovers from that old version. See Profile Manager - Create, remove or switch Firefox profiles

See also http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox

Hello Maggie.

The process is fairly easy, even for someone without much IT experience. Here's a quick guide:

1. uninstall Firefox 1.5 (this can be done through Windows Control Panel, under Programs and Features - I think). It's listed as Mozilla Firefox, most likely. No data will be lost in the process unless you specifically tell the uninstaller to delete your personal data;
2. download the latest stable version at getfirefox.com. It's totally free, as always;
3. run the installer you just downloaded and follow the installation process;
4. once installed, Firefox 3.6.3 will detect your Firefox profile and use it to make you feel at home, as always. I will remind you that some extensions may not work on the new version (Firefox will check for updates once you start the new version for the first time), and that Firefox 3.6 has many new and exciting features, so be on the lookout for them! I'm sure you'll like the new location bar suggestions (that are more intelligent and search your who history faster and more comprehensively), the new interface, the new bookmark manager (you can now add tags to your bookmarks so you can group the as you like), and many other things. I think that, once you run Firefox 3.6 for the first time, a tab will appear telling you what's new. You can explore it, of course.

If you need help with replacements for any extensions that may not work with the new version, I'm happy to help you. Just ask here.

What if I don't like the new version? When I first got this computer in Jan 2009 I installed the latest version of Firefox but didn't like it so I uninstalled it and installed 1.5 like I had on my previous machine.

Maggie, if you don't like the new version, you can customize it in a way that you like (I can help you with that, if you want).

There are known security vulnerabilities in Firefox 1.5 which are being exploited to infect people that don't like to upgrade with malware.

Which is to say, "if you don't update your browser, the boogieman will come for you".

It might sound a bit overdramatic, but it's true. It's common enough to find someone who got virus or malware while using update browsers, let alone outdated ones. And we're talking about people's safety here. Using malware, anyone may find a way to extract your bank account number, know when you're at home or not, steal your identity, your files, any kind of crazy stuff. Security is a very important thing in computers, and it is the top priority of Firefox, always. So please update, for your own good. If you don't like the new versions, as I said, there are ways to customize it (other browsers aren't really good at customization like Firefox is), and I'll help you if you want.

Thank you so much to all who have replied! You have been very kind and helpful.

I'm going to take a deep breath now and follow your suggestions for updating.

Hopefully I won't need to ask for more help, but I appreciate very much the reassurance that it's okay if I do!

Well, I uninstalled 1.5 and installed 3.6.3... so far so good.

However, one of the add-ons I had before was Fasterfox and now when I search for that add-on there are a BUNCH of them to choose from! How do I know which one I had before? Thanks!

Maggie, did the extensions you had installed disappear when you made the update? You can see the list of extensions by going into Tools > Add-ons > Extensions.

In any case, your old version was probably this one, which is not supported by newer versions of Firefox (hence why it disappeared). The best current version is this one, if you want to use a version that works with Firefox 3.6. Be aware, however, that it is an experimental add-on.

Thanks-- maybe I'll just do without it for now. But I'm also having a BIG problem with bookmarking. When I wanted to bookmark a page in Firefox 1.5, I just clicked Bookmarks, Bookmark this Page, then a drop-down list appeared showing my bookmark folders, and I clicked on the one I wanted to put it in.

Now it just says it bookmarked it and that's the end of that. There's no way to choose where it's going and I don't even know where it went.

Maggie, bookmarking with Firefox 3.0+ is made easier, but it's certainly different. Now, you simply click the star in your location bar and it will store that bookmark in a folder called Unsorted Bookmarks. If you want to further customize where it is and the tags and the title and stuff like that, you simply click the star again, and a popup will appear.

In short: -one click in the star to quickly bookmark in the Unsorted Bookmarks folder -another click in the star to customize the bookmark. This second click is basically the same as going into Bookmarks > Bookmark this page, as it will show the popup with the options and so on.

I hope this answers your question.

You can read more about it here:

http://support.mozilla.com/en-US/kb/Bookmarks#Making_new_bookmarks