Welcome to the Forums.
While OpenOffice 2.4 may have worked for you for a long time, it is an extremely old version. It was released Mar 27, 2008. Over 11 years ago.
That said, I'd like to recommend that you consider upgrading to the current version, which is 4.1.7 or go to LibreOffice, which has a more active development.
In regards to your actual question, usually when OpenOffice suddenly stops working as we're used to, it's due to a corruption of the OpenOffice User Profile.
More information is in
this tutorialIf you do decide to upgrade, due to the differences in the location where the OpenOffice User Profile is stored, an upgrade from 2.x to 3.x or 4.x will generate a new user profile.
Normally this is not the case as the profile location is specific to the major release number.