ATI Rage XL Removal

I've got an IBM eServer xseries 225 8649 type running XP Pro with SP2.
This system comes with a 7505 Intel Chipset with an on-board video
mini-pci ATI Rage XL PCI card. I would like to upgrade it to a Nvidia
G-Force 6200 graphics card that I have fitted into the AGP Pro slot on
the board but I only get 16-color (4-bit) video and the following error
in device manager:

This device cannot find enough free resources that it can use. (Code
12)

If you want to use this device, you will need to disable one of the
other devices on this system.

I have tried everything to remove all traces of the ATI drivers
(including Driver Cleaner!) but to no effect. I have even remove the
Rage XL mini pci card from the board but it still gives me the Code 12
error. I have check the BIOS configuration settings and I can't find
any way to point the video adapter at a PCI slot as there is with some
intel chipsets.

Perhaps it's just not possible to upgrade to a different graphics card,
but I'd like to explore all possibilities first before returning my
graphics card to the shop.

Thanks, Richard

I have been searching around trying to find any infromation on this and
found that ATI drivers are notoriously difficult to remove, that is why
I went down that route. I hunted the bios settings in the hope that the
system may mention something about disabling the video and redicting it
to a PCI or perhaps the AGP slot. I am working my way through
everything I can find.

I worked through the code 12 troubleshooting, but it doesn't help
either.