Have you tried the latest bios version 0011? Make sure to check whether the lan is enabled in the bios after the update.
There is a lan fix issue implemented in the last version.
Are you using any external lan card? if yes, remove it.
Re-install the lan driver again.
If the LAN Led does not blink when connecting the lan cable from your system to the router, then there must be something wrong with the onboard lan.
All the best,