Alright well this is my story. I had windows XP x64 installed and upgraded from a AMD Athlon 64 2800+ to a AMD Athlon 64 3800+ X2 and the ACPI didnt update. I read that if it doesnt update that a fresh install should fix the problem. I reinstalled XP x64 and its still showing ACPI singleprocessor under device manager. It there a way to manually change this?