GA-6VXC7-4X problem with WINDOWS XP

I have problems with my AGP card, a ATI RAGE 128,
in windows XP adn windows 2000:

1)
The system becames instable (hangs randomly,
the screen freezes, maybe audio keeps on for a while,
then it reboots). After reboot windows XP
shows a message like this:

A problem occurred with the video adapter driver
Report problem YES/NO


2)
The directx test (DXDIAG) of direct3D always hangs
in the same way... more often during the direct3D 8 test
and sometimes during direct3d 9 test


In the same system I have windows 98 and ME (multiboot)
and newer had anything like this, everything work fine.


.....
Tried cooling down the cards with oversized fan,
Tried reducing AGP to 1x and 2x in the BIOS,
Done RAM test,
Tried removing RAM from MoBo slots
Nothing...



Maybe someone out there can tell me what is happening
or has any suggestion

Thanks
U.Bruno


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If usefull I add an extract of my configuration

MoBo: GIGABYTE GA-6VXC7-4X VIA APOLLO CHIPSET
DRIVER VIA_4in1_443v (LATEST UPDATE from VIA)
RAM: 64MB slot1 512MB slot2
AGP CARD: RAGE 128 32MB AGP VGA TVOUT PAL
BIOS PN:11368107100
CARD PN:1026810700
DRIVER 6.13.3279 (LATEST UPDATE from ATI)
DIRECTX: 9.0(4.09.0000.0902)

Both windows XP and 2000 are clean install
with only the drivers listed above