A user reports "Internet is not working." Walk through systematic troubleshooting: (1) ping 127.0.0.1 (TCP/IP stack), (2) ipconfig /all (check IP, no APIPA 169.254.x.x), (3) ping default gateway, (4) ping 8.8.8.8 (internet reachability), (5) nslookup google.com (DNS working?), (6) tracert 8.8.8.8 (where does it fail?). For each step: what result means problem is at which layer.
