I've been running a new machine with an i350-T2 NIC in it for several months without a hitch until today, when I booted the machine (prior shutdown had been clean) and noticed that there was no network connection. I checked in Windows Network Connections, and both i350 interfaces were absent. I then looked in Device Manager, and the NIC was not listed there either. I immediately rebooted into a Windows PE 3.1 environment (from a flash drive), and it showed the i350 working perfectly. Then I rebooted again back to my normal install of Windows, and the i350 was back to working like nothing had ever happened. There were no errors in Event Viewer.
What am I to make of this? Is this a once-off freak event that can be safely ignored?