Can't connect/get computer to recognize android phone (OPO)
if you are on windows then you need to manually install adb driver for your device. steps are as follow

Right click on computer and goto manage.
then goto device manager
find your device and right click on it 
and from menu choose update driver

now choose let me choose

go next

now browse your google usb driver location

click next

after that you'll see adb driver name then clcik next to install drivers.

see this link for description

https://software.intel.com/en-us/xdk/docs/installing-android-debug-bridge-adb-usb-driver-on-windows