1.First go to start and then type cmd and then click ok, under cmd type ipconfig, then if you find out your ipv4 address is start with 169. This mean that you are not responding or your network in not working or maybe your server or isp provider has a problem or technical problem.
2.The next step is to ping your default gateway to find out if your computer is responding to a network you will receive reply indicated in the reply about your status of your connection on what network is connecting to internet.
3.The next step is to ping 4.2.2.2 and then it will reply,and if did not get reply you must call your service provider or isp.
4.the next step is to ping a particular site type ping www.yahoo.com and then you will receive reply to find out if this particular site is responding or to find out how it load this particular site you will see how packets are sent ,received that send and how many is lost.
5. If you did not get a reply by ping a particular site that is a DNS issue