You can reformat your hard disk and reinstall Windows XP on a system without messing around with Microsoft's Product Activation after the reinstall.
To backup the Windows Activation files before reformatting the hard drive:
1. Use Windows Explorer to open the C:\Windows\System32 folder.
2. Copy the WPA.DBL and WPA.BAK files to a floppy disk, CD, or USB Flash Drive.
To restore the Windows Activation files after reformatting drive & reinstalling Windows XP:
1. Decline the activation request at the end of the installation procedure, and restart Windows XP.
2. During bootup, press [F8] to access the Windows Advanced Options menu.
3. Choose the Safe Mode (SAFEBOOT_OPTION=Minimal) option.
4. Use Windows Explorer to open the C:\Windows\System32 folder.
5. If they exist, rename the new Wpa.dbl and Wpa.bak files to Wpadbl.new and Wpabak.new.
6. Copy the original Wpa.dbl and Wpa.bak files from the floppy disk or CD to the C:\Windows\System32 folder.
7. Restart the system.
Note: this doesn't apply if you make hardware alterations before restoring the Windows Activation files.
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