I received your PM but you didn't include your service tag in the message. Here is a direct link to the Windows 7 Intel 825xx 10/100/1000 Ethernet Controller Driver, which is for your integrated (wired) network card. What happens when you copy that file onto a flash drive and try to install it into your E6430? Are there any specific error messages that come up?
You may also want to try to download the Intel Device Manager Diagnostics Utility and run that to see if there are any problems with the network card itself.