Network & internet troubleshooting on Windows

Description

Troubleshoot network and internet problems on Windows PCs - no internet, "connected, no internet", slow or dropping Wi-Fi, DNS failures, one site or app not loading, VPN and proxy issues, IP conflicts and adapter problems - by testing layer by layer (adapter, IP/DHCP, gateway, DNS, route, port) with ipconfig, Test-NetConnection, Resolve-DnsName, pathping and the WLAN report, then applying targeted fixes before any network reset. Use whenever the user says their internet doesn't work, Wi-Fi keeps disconnecting, websites won't load, DNS errors, slow network, VPN won't connect, or "it works on my phone but not my PC" - even if they only say "the internet is down".