Thanks for the quick reply,
Core is running 810, two nics, set as DHCP. Pretty much stock standard as recommended. I don't get the lights for the lan when I plug the cable in and also when I power it on, no lights.
The Zotac-A-C has no hdd but it does have a wireless mini PCI card attached, don't know if that is interfering so will try pulling it out too.
I suspect it may be a bios setting or faulty ethernet adapter/port. I've installed ubuntu on a hdd and lspci will list a nvidia ethernet adapter but doesn't configure it automatically.
Another computer on the cable pxe boots fine so I suspect it is to do with the Zotac.