[CentOS] Video Card not recognized!!!

Hello List:

This is my first try to install CentOS 4.3 ia64. The motherboard is:

ECS Model K8M800-M2
Chipset VIAVT 8237

AMD 754Pin 3000+ CPU
512 DDR Memory


This MB has built-in Video. When I install 4.3 32 Bit OS, it installs fine.
But when I try installing 64 Bit OS, it does not recognize the Video Card.

Any suggestions?

Kirti