Q: My iPhone 4S has lost wi-fi capability.  It cannot find wifi networks known to exist.  It happened suddenly about 3 days ago.  I've rebooted everything that can be rebooted or reset.  No positive results.  Any help?

Hello Bj\'s rapid edge,

Thank you for using Apple Support Communities.

For more information, take a look at:

iOS: Troubleshooting Wi-Fi networks and connections

http://support.apple.com/kb/ts1398

1. Restart your iOS device.
2. Tap Settings > Wi-Fi and locate the Wi-Fi network to which you're connected.
3. Tap and Forget this Network.
4. Try to connect to your desired Wi-Fi network.
   Note: You may need to enter your Wi-Fi password again if your network requires one.
5. Turn your Wi-Fi router off and on2. If your ISP also provides cable or phone service, check with them before attempting this step to avoid interruption of service.
6. Update your device to the latest version of software.
7. Update your Wi-Fi router to the latest firmware2. For AirPort Base Stations, install updates using the AirPort Utility.

Unable to locate a Wi-Fi network

1. Verify that the network is available by tapping Settings > Wi-Fi and choosing from the available networks.Note: It may take a few seconds for the Wi-Fi network name to appear.
2. Move closer to your wireless router (access point) and attempt to locate the Wi-Fi network.
3. If you do not see the network you would like to join, you may be attempting to connect to a hidden network. Learn how to join a hidden network.
4. Supported Wi-Fi configurations vary by iOS device model. Find out which standards your device supports3.
5. Reset network settings by tapping Settings > General > Reset > Reset Network Settings. Note: This will reset all network settings including:
   • previously connected Wi-Fi networks and passwords
   • recently used Bluetooth accessories
   • VPN and APN settings

Have a nice day,

Mario