Windows 7 - RealTek Network Adapter/Controller not being found

Has someone faced the problem of the RealTek Network Adapter/Controller not being found. Yesterday morning my Internet connection went off and when I tried to repair it I got the following message:

The RealTek Network Adapter/Controller was not found. If Deep Sleep Mode enabled Please Plug the Cable

I searched the Net on my other Computer and found chapter and verse on this problem but none of the suggested cures worked and the Net remained off the whole day. Finally in the night in disgust I shut down the errant computer, unplugged all the cables attached to it, and went to sleep.

This morning I attached all the cables and restarted the computer and everything was back to normal again. I have searched this Forum but found no threads on this subject, so this post.

Could someone tell me what to do so that this doesn't happen again. After scouting the Net the only change that I have made is to uncheck the "Allow this Computer to turn off this device to save Power" Box.