My computer had a problem and I lost my system drive.
I have got my old Firefox 3 user files with a lot of bookmarks in.
but I cannot seem to find information for putting these bookmmrks into Firefox 4?
I solved my issue : Firefox makes backup bookmark files in the json format located in your user folder appdata/roaming/mozilla/firefox/profiles//bookmarkbackups
the boomarks.html file only kept the default firefox boomarks
The bookmarks are stored in a file called "bookmarks.html" and you should be able to just import them with the Bookmark Management options in Firefox 4 -- when managing your bookmarks, look for an "Import" option and choose "from file" then navigate to your old Firefox 3 user files and select "bookmarks.html."