How to Install Windows XP When the Error Code Is 4

1. Turn off your computer.
2. Remove the screws at the back of the case, and slide off the side panel.
3. Unscrew all PCI cards from the bottom half of the motherboard, and remove them from the computer.
4. Start the computer, and attempt to install Windows XP again. The process will begin without displaying the error code.
5. Shut down the computer, and reinsert your PCI cards one by one, attempting to start the installation process after each addition. Stop when you find the card that is triggering the error code, remove it from the system, reinstall the rest of your PCI devices and install Windows XP as normal.