Need Help on how to shut down avast

I really like AVAST antivirus and i feel really lucky to be able to use it…but i have this problem. I Need to play a specific game which Requires full of my system requirments (CPU,RAM,etc) and to do that i need to shut down avast…cause it is already getting much of my system.When i try to shut it down from boot i get this meassage: you are not the administrator please log in as admninistrator to disable.ANy help on how to disable it for a bit??

Disable avast providers (I recommend that, at least, you be offline to do so).