If you have a trial version of Office, perhaps the trial period has expired.
See http://support.microsoft.com/?kbid=831023 "How to convert an Office 2003
Trial edition to a full retail edition".
If you have a full version of Office, perhaps you have not activated the
license. In Word, click on Help | Activate Product. If you are already
activated, a message saying so will appear. If you are not activated, the
Activation Wizard will start.
