My brother has brought me a brand new Optiplex 990 desktop. While looking at its specification i come to know that it contain an integrated Intel 82579LM NIC and this PC is also running with Win 7 Pro 64-bit. Everything works fine but there is still single issue which i could not able to resolve yet. When i open the set-up process and got to my network settings, the icon which is meant for indicating NIC alternates in between "Network cable unplugged" otherwise "Enabled". However in some rare conditions "Identifying". I know that there is nothing wrong with the cable because i have used that network cable with other computer also. What could be the issue? Do you think that the Firewall program causing the problem? i have installed proper driver.