Give an exclusive irq to AGP

Hi,
I've a problem with my KT3 Ultra ARU. I installed a new graphic card
(Radeon 9800) and I moved/removed some pci card. Now the agp card shares the
irq (16) with "NEC PCI to USB Enhanced Host Controller(B1)". With the older
hw configuration (radeon 8500) I don't know if the irq was shared, but I had
no problems. With the new configuration I've some problems, for example if I
open a document with images in word 2003 the screen becomes black, and
sometimes that happens with games also. If I disabled Nec Host Controller
from Device manager and restart the pc all works well.
How can I give an exclusive irq to agp ?

My configuration:

AGP -> Radeon 9800
PCI Slot 1 (near agp) -> empty
PCI Slot 2 -> Ethernet card
PCI Slot 3 -> empty
PCI Slot 4 -> empty
PCI Slot 5 -> ISDN Modem

IRQ:
IRQ 01 Standard 101/102-Key or Microsoft Natural PS/2 Keyboard
IRQ 03 Communications Port (COM2)
IRQ 04 Communications Port (COM1)
IRQ 06 Standard floppy disk controller
IRQ 08 System CMOS/real time clock
IRQ 09 VAXSCSI Controller
IRQ 09 Microsoft ACPI-Compliant System
IRQ 12 PS/2 Compatible Mouse
IRQ 13 Numeric data processor
IRQ 14 Primary IDE Channel
IRQ 15 Secondary IDE Channel
----------------------------------------------------------------------------------------
IRQ 16 NEC PCI to USB Enhanced Host Controller (B1)
IRQ 16 RADEON 9800 PRO (Microsoft Corporation)
-----------------------------------------------------------------------------------------
IRQ 17 ASUSCOM P-IN-100(C,D) ISDNLink-00
IRQ 17 Realtek RTL8139 Family PCI Fast Ethernet NIC
IRQ 18 NEC PCI to USB Open Host Controller
IRQ 19 NEC PCI to USB Open Host Controller
IRQ 21 VIA Rev 5 or later USB Universal Host Controller
IRQ 22 Realtek AC'97 Audio for VIA (R) Audio Controller

Thanks in advance

Hio