After upgrading my macbook to El Capitan, Wifi does not connect automatically, needs to be told the name of the network also Macbook White early 2009 , 2 GHz Intel Core 2 Duo ,serial

After upgrading my macbook to El Capitan, Wifi does not connect automatically, needs to be told the name of the network also

• Macbook White early 2009 , 2 GHz Intel Core 2 Duo ,serial# W8905V754R1
• running El Capitan 10.11.2
• Wifi fails to auto connect, does not remember the network name either, needs to be manually connected
• reloaded the OSX two times but no help.
• Please share if you experienced a similar issue with a fix if possible