Hi, Dell has not tested XPS 730 with Windows 8. For more information on this you can check the link: [URL]  First step you can try is to check in BIOS if the Integrated NIC is enabled by following the steps below: [IMAGE] (Click on image for enlarged view) Once the Integrated network card is enabled, you can install the driver for Ethernet controller from link: [URL] Steps to download drivers: Please reply for further clarifications. 
I'm having a problem with my onboard NVIDIA nForce Network Ethernet card.  I have a XPS 730 running Windows 8 (64 bit).  What is the most recent date of the driver for this adapter?  I was attacked by a VERY bad virus (called SMALL) and have just got everything back to normal (I think).  It may be possible that the driver for my network card is corrupted.  Device Manager says driver is dated 2/23/2012  and the version is 7.3.1.7336.  Is this correct?  Two weeks ago the machine ran fine, Windows 8 installed without a problem.
onboard network card not functioning