180W Laptop charged with 45W charger, is it dead?

My brother gave me a dead gaming laptop (Asus GL503V) he bought on eBay some time ago, but it died a couple of months after. A couple of days ago he gave it to me, i noticed that the charger was relatively small to power such a powerful laptop, when i checked, the charger was 45W, while the laptop is 180W. I saw the computer working on my brother’s hands and the laptop would constantly start charging and stop charging every 20 seconds or so. He told me one day it just died out of nowhere (When i connect the smaller charger nothing lights up and nothing at all happens), could the motherboard be dead or could it just need a new charger?