Its always good to have a backup of all the things on your computer as you never know when it might crash.
Backing up bookmarks is an easy process to do. Just follow what is written below and you will be able to backup your bookmarks in no time.
By default Firefox backups bookmarks automatically when it is closed to C:\Documents and Settings\[username]\Application Data\Mozilla\Firefox\Profiles\[profile name]\bookmarks.bak. To restore, just rename to bookmarks.html.
Firefox will also archive, by default, the last five saves to the bookmarkbackups folder at the same location. The number of times it archives, can be modified by typing in the address field: about:config and changing the value for browser.bookmarks.max_backups.
You can also export your bookmarks with Bookmarks Manager.
To access Bookmark Manager in Firefox, click Bookmarks from the menu, then Organize Bookmarks. Once Bookmark Manager opens, select File/Export from the menu and select a destination to save the bookmarks.htm file. To restore, just select File/Import and browse to the location of the bookmarks.htm.
If your seeking an automatic solution, checkout Xmarks(formerly Foxmarks Bookmark Synchronizer) at . Xmark is a Firefox add-on that works silently in the background to keep your bookmarks synchronized between two or more computers. It works on safari and IE as well. It keeps your bookmarks and (optionally) passwords backed up and synchronized. Xmarks also helps you uncover the best of the web based on what millions of people are bookmarking.
Xmarks Bookmark Synchronizer add-on will need to be installed on all computers in order to synchronize.
Download: Xmarks