I've got an OptiPlex 7040 that sporadically shuts down without a BSOD and when it is powered back on, the NIC is disabled in BIOS. We have to reboot and re-enable it. When the issue started happening, after enabling it, even a normal reboot would disable the NIC again.
I updated the BIOS and other drivers, didn't spot anything in the event log... opened a ticket w/ Dell support and they eventually replaced the motherboard.
Issue still happens, just not as frequent. Anybody else see this issue related to NIC repeatedly becoming disabled in BIOS?
I've had the exact same issue on three of my 11 7040's in the last three months. I originally suspected foul play / sabotage but have discovered otherwise. I've set BIOS passwords on the three machines that did it and haven't had the problem since. I haven't tried a BIOS update though...