When your PC won’t connect online,Windows DNS server issues tend to be caused by either your Internet Provider (Verizon, Comcast, etc.), your Router, or your Computer’s settings.
Here are five possible solutions, in order of what is most likely to help:
1). In the case of your ISP being at fault, you’ll want to unplug the power from the modem, wait up to five minutes while powered off, then plug it back in. Wait another five minutes to finish booting up and reconnect to your Internet Provider. Also reboot your PC to force it to request new IP & DNS info.
2). In the case of the router, perform the same thing for the above, unplug the power from the router, wait five minutes, and plug it back in. After plugging it in, reboot your PC to request new IP & DNS info.
3). Contact your Internet Provider to ensure there is no account or billing issue. Stopping Internet access is a common method by which Internet Providers shut down accounts for a number of reasons.
4). You have a proxy setting enabled (usually caused by a virus or spyware infection). Go to your Internet Explorer, click on “Tools”, select “Internet Options”. On the “Connections” tab, click on “LAN Settings” and if a Proxy Server is enabled, uncheck it to disable it. Note: If this is the case, you should run Antivirus & Anti-Malware scans on your PC.
5). *Please note, this final step is a longshot, since static IPs and Windows DNS server info are rarely used, but I have seen it before.*
A static IP address has been setup on your PC with DNS info that is now out of date. To confirm this, go to your Start Menu, Control Panel, and open Network Connections. Right-click on your network connection, and select properties. From here you’ll need a box with a series of items checked off. Highlight the “Internet Protocol TCP/IP” (IPv4 one if it has both IPv4 and IPv6). From here your IP address and will either be set to “Acquire automatically” or “Use the following”. If they’re set to “Use the following”, note down the settings in case you need to switch this back, and then switch them to “Acquire Automatically”, hit OK or close on the windows you have open, and Reboot your PC.