Using Setup in Maintenance Mode
When you run Setup on a system that has Office installed already, you'll see the Maintenance Mode Options dialog box shown in Figure A.6. Use this dialog box when you want to add or remove features, when you need to repair an Office installation that is not functioning properly, or when you want to completely uninstall Office XP.
Figure A.6. After you install Office XP, running Setup displays the Maintenance Mode Options dialog box.
You can start Setup in Maintenance Mode by running Setup from the CD or network installation point, or by using the Add/Remove Programs option in Control Panel.
Adding and Removing Office Features
To change the list of installed Office features after running Setup for the first time, run Setup in Maintenance Mode and click the Add or Remove Features button. The resulting dialog box is nearly identical to the list of features available when you perform a custom installation, as described previously. You can also use this dialog box to change the configuration of a feature—for example, to change a feature that is installed to run from the local computer so that it runs from a CD or the network instead, using one of these techniques:
To add a feature so that it is available at all times, check the Run from My Computer, Run from CD, or Run from Network check boxes.
To configure a feature so that it is available for installation when needed, select the Installed on First Use option.
Repairing an Office Installation
The Windows Installer maintains a complete record of all Office components you've installed. If you accidentally delete a file or a Registry entry becomes corrupted after installation, the Windows Installer can automatically reinstall the component the next time you try to use it. In most cases, these repairs are automatic: If a key DLL for Publisher is missing when you attempt to launch the program, for example, the Installer starts automatically and reinstalls the missing file from the original installation source. You might need to supply the Office CD to continue.
If you suspect that some features of an application might be damaged, you can force Setup to inspect all essential files for that application and reinstall any files that are missing or corrupted. To use this option, choose Help, Detect and Repair. You'll see the dialog box shown in Figure A.7; click Start to continue.
Figure A.7. If you've inadvertently deleted one or more shortcuts for an application, use the Detect and Repair option to restore the shortcuts and any missing program files.
The Detect and Repair option works only on the application from which you run it. If you're unable to start that application, or if you suspect that several programs are damaged, rerun Setup in Maintenance Mode and choose Repair Office. This option lets you choose whether to completely reinstall Office using all the settings you originally specified, or whether the Windows Installer should look for missing or corrupted files and Registry settings and repair them as needed.
Uninstalling Office XP
The final option in the Maintenance Mode dialog box, Uninstall Office, lets you completely uninstall Office XP and all associated features and components. When you choose this option, you see one and only one dialog box asking you to confirm that you want to remove Office completely. If you click OK, the Windows Installer begins the uninstall process immediately.
Tip from 
Thanks to the Windows Installer's rollback capability, you can abort the uninstall process at any time before completion, and Setup restores your system to its previous state. A progress bar moves from left to right as the Windows Installer removes components; if you click the Cancel button, watch the progress bar move from right to left as the Windows Installer undoes its actions and restores the original configuration.
You should be aware of three caveats when uninstalling Office:
Uninstalling Office XP does not remove Internet Explorer 5. Depending on your system configuration, you might not be able to uninstall IE5 by using the Add/Remove Programs option in the Windows Control Panel, although you will still be able to remove Office. If IE5 was included with your operating system rather than installed as an upgrade to IE4, for example, it cannot be removed.
Using the Uninstall Office option effectively deletes virtually all program files and associated Registry entries. However, it leaves behind a considerable number of Registry entries associated with user settings and preferences, as well as some files that contain user settings. If you attempt to reinstall Office later, the new installation will use these settings. For instance, if you've defined alternate locations for documents, these will appear in your new installation, as will Excel macros in a leftover Personal Macro Workbook.
If you upgraded over an earlier version of Office, removing Office XP will not bring back the previous version. The only way to preserve older Office versions is to specifically choose that option by performing a custom install of Office XP in the first place.