This may or may not have something to do with Vista; I'm not really sure what causes this, but Vista is the OS.
This is some of the dxdiag information if that helps. I can post more of it if necessary.
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System Information
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Time of this report: 10/16/2008, 07:12:54
Operating System: Windows Vista™ Home Premium (6.0, Build 6001) Service Pack 1 (6001.vistasp1_gdr.080917-1612)
Language: English (Regional Setting: English)
System Manufacturer: ASUSTeK Computer Inc.
System Model: G2S
BIOS: Default System BIOS
Processor: Intel® Core2 Duo CPU T7700 @ 2.40GHz (2 CPUs), ~2.4GHz
Memory: 3070MB RAM
Page File: 1354MB used, 4987MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 10
DX Setup Parameters: Not found
DxDiag Version: 6.00.6001.18000 32bit Unicode