If you are using an AGP Graphics card, make sure it is suitable for your motherboards AGP Speed/Frequency etc...
If you are using a PCI Graphics card make sure your jumper settings for the CPU/PCI bus/multipliers are correct. Making the PCI bus settings higher than 33 will result in your PCI devices not working or damaging your cards. But all this depends on the motherboard you are using.
If you are using a PCI Graphics card make sure your jumper settings for the CPU/PCI bus/multipliers are correct. Making the PCI bus settings higher than 33 will result in your PCI devices not working or damaging your cards. But all this depends on the motherboard you are using.