1- How To Backup Firefox Bookmarks:
How to Backup Your Bookmarks Manually
From the Firefox menu bar go to Bookmarks > Organize Bookmarks to bring up your bookmarks manager. Now you want to click the top button that says Import and Backup.
Next, select Backup. This will bring up a “Save As” box where you can save your bookmarks to any location. Make sure you leave the bookmark as a .json file too. Since Firefox 3, this is the type of file Firefox uses for backups. If you wish to export your bookmarks as an HTML file, go to Import and Backup > Export HTML. That will give you the more traditional .html backup.
Recover Firefox’s Internal Bookmark Backups
Did you know that Firefox has been backing up your bookmarks all along? They are in your Firefox profile folder. First thing you need to do is find your profile folder for Firefox. Depending on your operating system this may be in a different location. If you are unsure, be sure to check out this previous post:
Once you make it in there you should see a folder named “bookmarkbackups”. Double-click that folder, and there you have some of your saved bookmarks that you thought you had lost waiting for you to restore them. If you want more backups to be saved (default is 5) then check out this previous article on the simple about:config tweak you will need to do.
2- How to backup Google Earth Places:
Copy myplaces.kml file (For Windwos 7: C:\Users\<USERNAME>\AppData\LocalLow\Google\GoogleEarth\myplaces.kml)
3- Backup Hosts File
4- Backup IE Favorites
5- Backup Outlook Files