After waking up from standby mode, my Lenovo X200 laptop cannot connect to known Wi-Fi networks (both at home and office). It uses Intel WiFi Link 5100 AGN card and Microsoft's driver with Windows 10 Build 10586.36. I try setting the 802.11n Change Width for band 2,4 to Auto. It works! Set 802.11n Chanel Width for band 2.4 to Auto Hope this will save you time if run into the same situation. Be HAPPY!
Practice until you can't make it wrong.