A few months ago I had downloaded a JaS 10.4.6 SSE2/SSE3 Intel/AMD build and networking worked fine. After I installed this one, I couldn't get Ethernet to work. In System Preferences Network settings, Network Port Configurations lists Ethernet but unfortunately  it is grayed-out and I cannot select it.
 
Any ideas on how to get this working? All wires are plugged in correctly, Windows XP ethernet worked fine.

Here's my computer info:

Computer brand & model: Dell Dimension 2400
 
Processor: 2.53GHz Intel Pentium 4 Processor w/SSE2
 
Random Access Memory: 1GB (2 X 512MB) PC2700
 
Graphics card: NVIDIA GeForce FX5200 128MB (Quartz Extreme, OpenGL, and Core Image are supported)
 
Motherboard: Intel i845G Chipset
 
Network: Integrated 10/100 Ethernet
 
Audio: Realtek AC-'97 Codec (input/output works fine, fully supported)
 
Hard drive: 74GB 7200RPM Internal HD (full install of Mac OS X on, not a dual boot)
 
Mac OS x86 Build:
 
Mac OS X 10.4.8 [JaS AMD-Intel-SSE2-SSE3 with PPF1 & PPF2].iso
 
Options installed from the DVD setup:
 
10.4.4.loginwindow.pkg
 
10.4.8.intel.pkg
 
NvidiaNV40.pkg
 
Sigmatel9220Audio.Support.pkg