Why is my 360 restarting over and over.

So i have an old 360 and i havent touched it in awhile but recently we want to use it for netflix. It updated after connecting it to the wifi. And then after turning it on now it will run for a little bit then make a click sound and power off and restart, turning itself back on. It will stay on if i dont run any app or game, somtimes. But as soon or shortly after starting a app it will make the click sound and restart. I took it apart and cleaned the years of dust out of it and put it back together and it still does it. Id like to know what i can do to fix it.