Do you have the latest drivers.
What about the openGL drivers?
Or probably a new video card.
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VISTA 64Bit
C2Q Q6600 2.40G with Tunic Tower 120
8800GTX ( Step up program )
GIGABYTE GA-P35-DS3R 775 with Crucial Ballistix 4GB
Acer 22" Widescreen LCD Monitor