We have a LP6 with a Siemens 840d. The motherboard went on the PC attached to LP6. We replaced the motherboard. No errors on PC or as far as Windows NT is concerned. Start Ncdde and then Powerlink and it says No NC Connection. Having a hard time determining what is wrong. The motherboards are quite similar. Siemens tested pci card and that is good. Do machine manufacturers have custom bios programs on their motherboards? This is the only thing I can think of.