Wolfenstein: Enemy Territory needs this as I found on one particular site:
Minimum PC System Requirements:
Processor Type: Intel® Pentium® II ;processor, AMD Athlon™ processor ;Processor Speed: 400MHz
Operating System: Windows 95/98, Windows Millennium Edition (Windows Me), Windows 2000, Windows NT 4.0, Windows XP
System Memory: 128MB RAM
Hard Drive Space: 800MB
Video: 3D hardware accelerator with 16MB VRAM with full Open GL support, 16-bit high-color Video mode
Sound Card: DirectX 3.0-compatible or higher
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Supposedly, your graphics support it:
http://support.intel.com/support/graphics/sb/CS-004662.htm
But you need the latest driver if you don't have it already, from Intel: (for xp)
http://downloadfinder.intel.com/scripts-df/Product_Filter.asp?ProductID=865
This 82845G should work (though earlier you said it was 82810E, which may not work).
But Intel also has a game troubleshooter that will talk about changing settings for OpenGL. The search area is:
http://support.intel.com/support/graphics/sb/cs-010470.htm?iid=graphics+845main&
Though Wolfenstein is not in the list. One such instance is:
http://support.intel.com/support/graphics/sb/CS-008649.htm
Which talks about changing an OpenGL setting, you might try that?
Otherwise, if you have the 82845G with the latest graphics and DirectX, the game should work. Suspect something else.
If you have the 82810E then you need a video card. I think the 82810E supports OpenGL 1.1. OpenGL 2.0 just came out but the latest may be 1.3. So that could be the issue there.
Other than that, you could have other issues still. Maybe RAM issues or maybe the program just didn't install right? Settings problems? What about an Antivirus/firewall causing trouble?
Good luck