Ethernet connection error

I have been having problem getting onto any website for past week even when wifi shows network connected and having internet access. The other part of the problem is when connected through ethernet directly to modem, laptop tells it is unidentified network, the diagnostic identified error as " local area connection does not have a valid IP configuartion." The first part is still not fixed but I have got no suggestions for fixing Ethernet connection part so I am asking question separately.