If all new and existing documents are locked for editing, then it's
probably because you have not activated your Word/Office software, or
because you have an expired trial version of Office 2003. What happens
if you start Word and click on Help | Activate Product? If you are
already activated, a dialog box saying so will appear. If you are not
activated, the Activation Wizard will start. If you have an expired
trial version, a dialog box will prompt you to enter a valid product key
or purchase a key online.