What exactly are you trying to achieve? If you want to assign IRQs for some devices manually, go ahead and Reserve those IRQs in BIOS. XP will automatically assign new IRQs to the devices which previously used Reserved IRQs. You should be able to assign Reserved IRQs manually now. You may also need to disable PnP OS in the BIOS though. Question is why would you wanna do any of this stuff? Gone are the days when people had IRQ nightmares and device conflicts. I would leave the task to XP. It does a fine job in this department.