I have two laptops on my home network. Both connect with WiFi. Both are Dell Inspiron 15's, but one is 7000 series and the other is 5000 series. Both run Avast Free. The 5000 series started showing "No Internet" in the browsers. Windows network troubleshooting says DNS Server not responding. I went through everything suggested about DNS problems, but I skipped the disable your antivirus, since the same one was running on the other laptop. Anyway, problem persisted with both onboard adapters ( ethernet and wifi ) disabled and a USB wifi adapter added. It would run to load a browser after rebooting ( no matter which adapter I was using ), but after a few minutes, the DNS server not responding appeared. Finally, I disabled AVAST, and everything worked. I started to uninstall Avast and it gave me the option of "repairing" the installation, so I chose that. Did not work, so I uninstalled AVAST. Now all is working fine, but I really like AVAST, and would like to find a way to continue using it. All suggestions will be appreciated.