Actually I was about to edit and chime in on that, did some more reading and the difference between the two is only about 15W which the Alienware AC adapter can easily handle.
Hopefully so but I note power supplies also get weaker as they age. And they have already bumped up the RAM which will consume more power, albeit not a lot. Switching to an SSD will hopefully save some over the HD - but again, not a lot.
That said, I also said a hungrier graphics solution puts greater demands on the aging regulator circuits and cooling. Taking just the power supply out of context

does not change the validity of my point.
...the components within will be fine.
??? Huh? You don't know that. All electronics age - especially those that subject to regular large swings in temperatures - such as the voltage regulators I just mentioned - again. And it is important to note the electronics in notebook go through significantly greater temperature swings compared to PCs which typically sit in environmentally controlled facilities, and are housed in large PC cases instead of cramped notebook cases.
Every capacitor, resistor, diode, IC, even solder joint is at least 8 years old. Even the lid hinges are old and the cables that run through them have likely been flexed 1000s of times.
The mere fact this is a used computer means you don't know the components inside will be fine - and this is especially true since you have never seen this computer, or know what kind of abuse it has sustained by its previous owner (or owners!).
Here we agree, however the laptop isn't just going to up and die. I have a Gateway C2Q based laptop that is much older and it still runs fine.
Again, you don't know that. Your sample-size-of-one experience does not set the standard. Anecdotal evidence is not evidence.
I have a Toshiba notebook that is almost 10 years old still chugging along. But I have a 6 year old Dell with a failed motherboard too.
You've claimed to have or work in a shop. Surely you have seen computers come in that have failed that were only a few years old? I surely would not have had a long and lucrative career as an electronics technician if computers, TVs and home audio electronics hardware never failed prematurely.
While it is possible electronics hardware will last 10, 15 years or even longer, it is also possible it will go up in smoke in 5 years or less - or 1 day after the warranty runs out.
That system is Windows 10 supported.
Not officially.
I see no point in any of this discussion. None helps the OP. So let's get back to helping him.