Why is my Dell Inspirion N4020 is not connecting to wireless internet

Did you recently upgrade to Windows 10? If yes did it stop working after that? Is it showing a connection with the yellow exclamation triangle with computer symbol at the bottom right of your screen on the taskbar?

If yes try uninstalling anti-virus applications such as Trend Micro, Mcafee and/or update them to the latest version as the version that you have may not be compatible with Windows 10 and may be causing issues with the connection to your Netgear Router.

Also try typing this in the command prompt as administrator 'ipconfig /flushdns'.

You can do this by pressing the start button or opening the start menu located at the bottom left of the screen and typing in cmd then right clicking on the cmd search result and pressing run as administrator. Then you type the command I mentioned above to flush the DNS resolver cache which may solve your issue.