PC Hardware wrote a small article which covers the ACPI problems. Readers can find out what ACPI is, how to remove it even if the computer BIOS doesn't have an ACPI disable setting and how to troubleshoot ACPI problems. With so many ACPI related posts on every forum on the net we should ask if ACPI usage is reliable or recommended. We tried to answer to both questions.
Ed Note: I personally do not use ACPI as it frees up IRQ9 (much needed resources in Windows) :)