You may experience the following error when installing Windows XPService Pack 3 (SP3) when installing on Intel iMAC using Bootcamp to run Windows XP.
This happens because iMac uses EFI file format which Windows XP does not support. To workaround this problem, add a registry key as follows:
1. Click Start – Run – Type “regedit” and press enter.
2. Navigate to
[HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Setup]
HKEY_LOCAL_MACHINE
\Software
\Microsoft
\Windows
\CurrentVersion
\Setup
3. In the right pane, Right-click and select New – String value4. Name it as “BootDir” and set its value to “C:\”
This should help. Try installing SP3 and should work fine.