Alright, What I did is disable the "Wi-Fi Protected Setup (Also called WCN 2.0 in Windows Vista)" area. Go and access SETUP>>WIRELESS SETUP>>Manual Wireless Connection Setup. Then untick the WCN. (Untick the "Enable").
With this, I do not need to change to 20MHz and still using b/g/n and still using WPA2. Heh heh
LAPTOP CAN'T DETECT UNIFI ROUTER, but other devices can and are connected!