Not connecting to wifi

@lauraholder not giving us a lot of information here. Would be nice to know what OS you are using and what you have already tired and checked.

Anyhow, first thing I'd check is if the computer even knows the WiFi card is there. Right-click your Start button, open Device Manager, and look under Network Adapters. If the Wi-Fi card has a yellow exclamation mark, you just need to uninstall it, restart, and let Windows reinstall the driver. If it’s completely missing from the list, the motherboard physically can't see it.

It is also possible that this is a firmware/software issue. Disconnect the AC adapter and turn the laptop off. Hold the power button down for a solid 30 seconds to drain all the leftover power from the board capacitors. Boot it back up and see if the Wi-Fi wakes up.

If that did not work either, time to look inside. Remove the bottom cover and locate the Wi-Fi card plugged into the motherboard. Make sure the two antenna wires (usually one black and one white) didn't pop off the connectors. If they look good, take the screw out, pull the card and wipe the gold contacts with a lint-free cloth and some isopropyl alcohol, push it right back in so it seats firmly. If you put it all back together and Device Manager still shows absolutely nothing, that WiFi card has failed and needs to be replaced.

Use the Inspiron 7586 Service Manual to work on your laptop.