Upon finishing my new PC, I decided to let Windows 7 update itself while I take a nap. After a half an hour I returned and rebooted the machine. Much to my horror, the integrated Ethernet had entirely ceased to function! Indeed, device manager no longer showed any LAN devices. Even more puzzling was the error message I received while trying to reinstall my motherboard's integrated LAN drivers: "Wait ... what?!", I immediately exclaimed aloud. A few Google searches later, the problem was made quite clear. Apparently, integrated devices on several motherboards tend not to wake up after Windows 7 goes into sleep mode. The precise cause eludes me, yet one easy solution is as follows: Turn off the PC Switch off the power switch at the back of the PC if it a desktop. Laptop owners simply unplug the power adapter. Wait a few minutes while the capacitors lose their charge and the RAM clears. Turn on the PC and verify that the LAN or whichever device was giving the deep sleep error now works. If not, then you could turn off the PC and remove the RAM for a minute. (Don't forget to touch the PSU before handling the RAM, though!) Now that you've fixed the immediate issue, let's prevent it from happening again. Open up Device Manager Right click the device which formerly gave the error. Click on Properties Click on the Power Management tab. Un-check the box for the setting "Allow the computer to turn off this device to save power." Click OK to save your changes. Of course, you could simply disable sleep mode entirely. My motherboard is a GIGABYTE X58A UD3R, but I suspect this issue resides amongst other brands as well. If anyone has received this error message and this post fails to resolve the issue, then let us know!