If it is not working,

* check whether it is plugged or not.
* check the cables or electricity system of your house.
* check your remote controller.
* Some air-conditioners don’t work when you start or stop. So, wait for a little while or try again.

If it is not cooling,

* check air-intake connections or pipes.
* check heating control again.
* shut the doors and windows in your room.
* try drawing the curtains in sunny days.