Reinstall Windows over SP2

After being battered by a virus and my meager attempts to eradicate it, my PC is essentially nonfunctional. I need to reinstall Windows XP without erasing my hard disk and all my data. But when I pop in my XP CD and try to run Windows Setup, I'm told that I can't install Windows over a newer version. It doesn't make sense: I'm installing XP over XP!

The problem is that you're not using Windows XP, you're using Windows XP Service
Pack 2 (or SP2), which Microsoft considers a newer version of the operating system. If you're like most of us, the service pack a bundle of patches and updates assembled by Microsoftwas installed automatically as part of the Windows Update service.

Does this mean your old XP CD is useless? Not necessarily. If you need to reinstall Windows, you have two options. First, you may be able to uninstall SP2 via the Add or Remove Programs control panel, and then reinstall XP. Alternatively, you can use your existing Windows CD to create a new Windows disc that includes SP2 and then use the new disc to reinstall Windows. This second process is called slipstreaming, and while somewhat arduous, it's worth the trouble, particularly if you want to be prepared for future PC emergencies (if your PC won't boot you won't be able to remove SP2, which means you won't be able to reinstall Windows, and your remaining option will involve crushing your PC with a large, blunt instrument).

To start, you'll need a real, original Windows XP CD; if you only have a restore disc or an XP CD with SP1 already installed, you can't use this fix. You'll also need a CD writer, a blank disc, and a full-blown CD burning application, such as Roxio Easy Media Creator or Nero Ultra Edition.

Windows Explorer's built-in CD burning feature won't cut it.

First, open Windows Explorer and create two new folders in the root folder of your hard disk: c:\xp and c:\sp2. Pop your original XP CD in your drive, highlight everything in the root folder of your CD (press Ctrl-A), and copy (drag) all the files on the CD into the c:\xp folder you just created.

Next, download the "Full Network Install" release of Service Pack 2. The filename is WindowsXP-KB835935-SP2-ENU.exe. Save this 270+ MB file to the c:\sp2 folder on your hard disk, and when it's finished downloading, rename the file to sp2.exe.

Open a Command Prompt window (go to Start --> Run and type cmd.exe), and type: c:\sp2\sp2.exe /integrate:c:\xp

If you get an error stating "This Service Pack cannot be integrated into a destination that also has integrated Software Updates," it means your CD is not a true, original Windows XP CD and thus can't be slipstreamed. If you get a "not a valid Win32 application" error, the patch you downloaded is corrupt; you'll need to delete it and download it again. If you get the cryptic "file too big for memory" error, you're short on disk spaceyou need at least 1 GB of free space after you've copied the setup files.
You'll need one more thing from your original Windows CD. Download IsoBuster from
CD Recovery | CD DVD Data Rescue software, featuring BD HD DVD, and run the program. In the main IsoBuster window, select your CD drive from the list and highlight the Bootable CD folder on the
left. On the right, you should see an .img file (e.g., Microsoft Corporation.img or possibly BootImage.img). Drag this file into the c:\sp2 folder on your hard disk.
Next, open your CD burning software, and start a new "Bootable Disc" project (in Roxio) or "CD-ROM (Boot)" project (in Nero). When prompted, specify these settings:
Bootable disc type: no emulation Boot image data/image file: specify the .img file you extracted with IsoBuster
File system: Joliet
Sector count (boot section): 4 sectors
Load segment: 0x7C0
Volume label: use the same CD volume label as your original XP CD
In most CD-burning programs, you'll be prompted for this information in a piecemeal fashion via a series of dialog boxes once you start the CD project. (Consult your application's documentation for additional settings necessary to create bootable CDs.)

When given the opportunity, add the entire contents of the c:\xp folder to your project, and then burn the CD. When the burn is complete, you should have a bootable Windows XP SP2 CD, which can be used just like your original XP CD. You can test the CD by using it to boot your system, as described in "Boot with the Windows CD." Once you're sure the CD works, you can delete both the c:\xp and
c:\sp2 folders.

To use the CD to reinstall Windows, you have two options: insert the new CD while Windows is running, or if you can't get into Windows boot off the CD. In either case, choose the option to upgrade Windows rather than performing a fresh install, so that Setup can retain your installed applications and all your settings. Then, just follow
the on screen prompts to complete installation.

Unless you choose to format your hard disk, all your data will remain intact.