The obvious conclusion (to me) is the laptop is doing something detrimental. I'm certainly not planning on using another power supply to try it. But before I discard it totally, I thought I'd ask here if there is anything that might be worth trying.
Given that his machine has clearly passed it's prime - it's not a big deal. But it's nice to have.
I doubt it makes any difference - but it's an ASUS X53S.