The ability to uninstall Windows XP Professional from your computer is a completely new one to the Windows world. For many years now, smart installation routines have existed (now perfected by the Windows Installer and its MSI packages) that allowed you to effortlessly uninstall, modify, repair, or roll-back installed applications on your computer. Now in Windows XP Professional, Microsoft has delivered this same functionality to the operating systemalmost. Yes, as is the case with everything too good to be true, there is a catch to this as well.
Your ability to uninstall a Windows XP Professional upgrade installation hinges on several requirements which must not change from the time of the upgrade to the time of uninstallation. These requirements are
The installation must have been an upgrade from one of the following operating systems: Windows 98, Windows 98 Second Edition, or Windows Millennium Edition.
You cannot convert a volume to NTFS.
You cannot convert a volume to a dynamic disk.
You cannot create or delete a volume.
You must have at least 300MB of empty space available for the uninstall files.
You must not delete the uninstall files from your computer (even though you'll be prompted to do so by the Disk Cleanup Wizard 30 days after the upgrade).
If the day comes when you need to uninstall Windows XP Professional, and you meet all of the stated requirements, you can uninstall Windows XP as follows. Note, however, that there's one gotcha: You'll have to reinstall your applications after the reversion to the previous operating system.
Back Up for Safety!
Always back up your data before performing any major disk-intensive evolutionincluding uninstalling Windows XP Professional. See Chapter 25 for more information on using Windows XP's ntbackup.exe utility.
Open the Add or Remove Programs applet in the Control Panel.
Select Windows XP Professional from the list of currently installed programs, as shown in Figure 3.27.
Follow the onscreen prompts to complete the uninstallation. You will be prompted at least two times before actually starting the uninstall process. This is a one-way process, hence the extra confirmation page before being committed to the uninstallation.
Figure 3.27 Locating the Windows XP Professional uninstallation.
Alternatively, if you want to uninstall Windows XP Professional from the command line, you can do so using the following procedure.
Restart the computer using the Safe Mode with Command Prompt option. You will need to log in with local administrative privileges.
From the command line, enter the following command: x:\windows\system32\osuninst.exe, where x is the location of the Windows XP Professional uninstallation.
Follow the onscreen prompts to complete the uninstallation process.
After the uninstallation is complete, you will need to reinstall any applications that you had installed since the time of the upgrade.