All you need to just reset the user profile. All the data user-related are stored in a dedicated folder, often called the user profile. You can check its location on your HDD in the menu Tools>Options>OpenOffice.org>Paths
Most of the folders mentioned in that dialog are in the OpenOffice.org user profile.
The folders are hidden by default, make sure your file explorer is configured to display the hidden files and folders (for Windows users, see this post).For Windows users:
- Operating systems before Vista: C:\Documents and Settings\<user name>\Application Data\OpenOffice.org\3\user\
- Operating systems from Vista: C:\Users\<user name>\AppData\Roaming\OpenOffice.org\3\user