Hey Sorry to hear you that Please read the article it will help you to sort your problem https://support.mozilla.org/en-US/kb/cant-add-change-or-save-bookmarks

You can check the bookmarkbackups folder in the profile folder on the Windows XP computer and copy the JSON backups to the profile folder of the Windows 8 computer. Then you can restore the most recent JSON backup to get the bookmarks. Note that restoring a JSON backup will replace all current bookmarks. If you can still start Firefox on the Windows XP computer then you can also create an HTML backup. *https://support.mozilla.org/kb/restore-bookmarks-from-backup-or-move-them *http://kb.mozillazine.org/Backing_up_and_restoring_bookmarks_-_Firefox ----- You can use this button to go to the current Firefox profile folder: *Help > Troubleshooting Information > Profile Directory: Show Folder (Linux: Open Directory; Mac: Show in Finder) *http://kb.mozillazine.org/Profile_folder_-_Firefox XP: *C:\Documents and Settings\<user>\Application Data\Mozilla\Firefox\Profiles\<profile>\ Windows 8: *C:\Users\<user>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\ "AppData" (XP: Application Data; Mac: ~/Library; Linux: ~/.mozilla) is a hidden folder. *http://kb.mozillazine.org/Show_hidden_files_and_folders See also; *https://support.mozilla.org/kb/Recovering+important+data+from+an+old+profile *http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox