Well I don't know about your LAN Problem but for the sound, I would use AppleHDA Patcher, if VoodooHDA doesn't work for you.

First of a you need to remove VoodooHDA files and to restore the AppleHDA.kext.
The more you'll need some Linux system to do so. - Just use some Knoppix CD or something if you don't have one installed.
Get latest AppleHDA Patcher here: http://www.insanelymac.com/forum/ind...howtopic=32859

1. Go to /Library/PreferencePane and delete Voodoo.PrefPane
Go to /System/Library/Extensions and delete VoodooHDA.kext
2. It's not allowed to post MacOS X files here, but you'll find AppleHDA.kext on filestube.com
Otherwise you can extract it from you OSInstall.mpkg of your DVD using Pacifist.
3. Once you have back AppleHDA.kext restore it using KextHelper b7 get it here http://cheetha.net/
4. Boot into your Linux system, open up some Terminal and browse to /proc/asound/card0 using cd command. There should be something named codec#0 - might me named similiar.
5. Write it's content to some file using "cat codec#0 > dump.txt" save dump.txt to some USB Stick or alike so you can acess it from OS X.
6. Drop dump.txt onto Patcher Icon, wait till its done and hopefully boot into to system with working sound. Maybe you'll have to change your output device from Headphones to Line-Out into SystemConfiguration first.

Good Luck.

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