If you are unable to connect to your WiFi and you don’t see your WiFi network, your WiFi may be turned off on your device:
If you are on a mobile device, go to Settings and turn on WiFi
If you are on a laptop, look for a WiFi switch on the computer, a WiFi symbol on the display or a button on the keyboard (press Fn + WiFi button)

The Modem should be centrally located to the devices needing to connect to it
The Modem should be placed in an upright position for proper antenna alignment
Ensure your modem is clear of electronic devices that cause interference, including but not limited to: microwaves, cordless phones, Bluetooth devices and baby monitors

Forgetting WiFi networks allow your computer to reset some settings, such as usernames, passwords, or configurations that may allow you to reconnect again.

See below and select your device type for instructions.

Take your non-connected device to the same room as the modem and try connecting there

Restart your computer, tablet or mobile device by allowing it to power down and then turn it back on. Restarting your WiFi device can often resolve internal issues that may be causing WiFi connectivity problems.

If you still can't connect to WiFi after restarting your device, try restarting your modem. Unplug the power cord from the back of the modem. If you also have a router (for home/wireless networking), please unplug its power cable as well. After 10-15 seconds, plug the modem back in. Wait 10-15 seconds for the router to acquire the connection and send it out to your network, then test your connectivity.

Tap Settings and go to WiFi
Tap the exclamation mark beside your WiFi network name and select “Forget This Network”
Toggle WiFi off and then back on to have the device scan for available WiFi networks
Tap the WiFi network name associated with your WiFi Network
Enter your WiFi password when prompted then tap Join

Click on the WiFi Icon along the top menu bar
Click on Open Network Preferences at the bottom of the drop down menu
Click on WiFi in the menu on the left
Click Advanced located at the bottom right of the pop-up window
Select the WiFi network you want to delete, and click the minus sign, then click OK
To reconnect select your WiFi network name from the drop down menu. If your network name is not listed, please select Join Other Network at the bottom of the list then select Show Networks, select the network name and click Join
Type in your WiFi password and click OK

From your Home screen, tap Applications
Tap Settings and then tap WiFi
Tap the WiFi network that you are connected to and tap “Forget”
Toggle WiFi off and then back on to have the device scan for available WiFi networks
Tap the WiFi network name associated with your WiFi Network
Enter your WiFi password when prompted then tap Connect

Click on the WiFi Icon in the bottom right hand corner of your screen (for Windows 8, make sure you are on desktop view)
Click on Open Network and Sharing Center
Click on Manage Wireless Networks
Right click on the network name and select Remove Network
Click back on your browser and select Connect to a Network in the Network and Sharing Center
Select your WiFi network name and click Connect
Type in your WiFi password and click OK
If prompted, please select Home Network

From the home screen, swipe left to the Application list, then tap Settings
Tap WiFi then choose Advanced
Tap and hold on the network you want to forget, then tap Delete
Toggle WiFi off and then back on to have the device scan for available WiFi networks
Tap the WiFi network name associated with your WiFi Network
Enter your WiFi password when prompted then tap Done