On a x86-processor-based computer running Windows NT, the Windows NT Hardware Abstraction Layer (HAL) may assign an I/O port address or memory resource for the new PCI device that overlaps with an existing PCI device, causing a PCI resource conflict.

Normally, the system BIOS is responsible for setting the PCI device resource requirements. When Windows NT loads, the HAL sometimes moves the PCI device resources as they are dynamically configurable.

To prevent the HAL from moving PCI resources, add a /PCILOCK switch to the end of your boot.ini file.

Note: Only those HALs shipped by Microsoft will recognize this switch, if the system BIOS settings appear to be correct and complete. The Windows NT 4.0 HALs that currently have this fix are: HAL.DLL, HALMPS.DLL, and HALAPIC.DLL.

If the adding of a PCI adapter causes the system to hang during boot, remove the PCI adapter and reboot the system. Modify the BOOT.INI file by adding the /PCILOCK switch. Shut down the system, add the new adapter card, and reboot the system.

Other things you can try are:

- Insert the PCI adapter card in a different PCI slot.
- Change the driver load order for the conflicting PCI adapters. This is not always possible when the types of drivers loaded have to be in a pre-determined order.