Windows 7 Home Premium Service Pack 1
RealtekPCIe GBE Family Controller
With no apparent change in software or configuration, I am getting the 'Network cable unplugged' error. The cable connects another PC just fine so both the cable and router are OK.
Have you tried to restart the computer. I know it's obvious . but if you have not .. it's hard to go further .. I have seen this happen to some computers .. and then after restart .. it works fin again.