hello keven702, deleting the history in firefox isn't an action that's undoable. if you don't have any other form of backup of your hard-disk available then i fear that this data is lost for good.

for future reference: all your important personal data in firefox is saved in the profile folder, so a backup every now & then might help avoiding another loss of data: Back up and restore information in Firefox profiles

On Windows XP your chances are next to nil unless you have a backup copy of places.sqlite. On later Windows versions you might have luck with restoring a shadow copy of the places.sqlite database file that stores the bookmarks and the history, but this isn't possible on Windows XP.

There is a backup of your bookmarks. But not much else.

These can't get your data back, but will help in the future.

These add-ons can be a great help by backing up and restoring Firefox

FEBE (Firefox Environment Backup Extension) {web link} FEBE allows you to quickly and easily backup your Firefox extensions, history, passwords, and more. In fact, it goes beyond just backing up -- It will actually rebuild your saved files individually into installable .xpi files. It will also make backup of files that you choose.

OPIE {web link} Import/Export extension preferences