Broadcom Netlink (TM) Gigabit Ethernet diappears

No. I talked to Dell yesterday and they updated all the bios and reinstalled the driver and it worked fine until this morning and I had to reinstall the driver again. So its ok now. Thank for your response.

Make of model and version of Windows?

Have you tried disabling the onboard Ethernet via the Dell BIOS, restarting Windows and then powering down.

Then powering up, going into the Dell BIOS and re-enabling it and loading WIndows again.