Windows won't install on my PC

Good evening, or maybe good morning depending on where you all are 🙂

So, I've been spending my entire day trying to fix a friend's PC without any luck, so I was hoping someone here might be able to point me in the right direction.

The issue:
( Windows XP ) After booting up, it reaches the login screen (username/password), but then after about 5 to 25 seconds, the whole computer just shuts down. The only way to actually get into the OS is by using Safe Mode, where everything seems fine. To troubleshoot, I tried plugging her hard drive into my own PC to see if the error followed the drive, and sure enough, it did—my machine hit the exact same wall. I eventually decided to just wipe the drive and perform a fresh install of Windows XP on her hardware, but even during the setup process—you know, when it says "39 minutes remaining" and all that—the PC just dies. When I reboot, the installation doesn't pick up where it left off. At that point, I figured the drive itself might be shot, so I grabbed my backup drive, a Seagate 250, and tried installing Windows XP on that instead, but the result was identical. I even tried installing Windows 7, but it gets to the loading screen and then cuts out right when the actual installation is supposed to kick off.
It honestly makes no sense why this is happening, so if anyone has any insight, please let me know... By the way, I don't think it's the power supply, because I swapped in my own CX600 W and the exact same errors occurred.
What confuses me most is how the exact same failure happens on her machine when I plug in her drive, yet when I take one of my working drives and put it in her machine, it won't even allow an installation to start.

The PC is pretty... well, it's a budget build, but she doesn't need anything fancy other than watching movies, so it’s old enough that I can't really swap parts from my own rig to test them without making things more complicated.

Specs:
Motherboard: MCP68M-M2
RAM: 2x 512MB 800MHz
Graphics: Integrated GeForce 7050
Hard Drive: Maxtor 160GB
Power Supply: 420W

Anyway, sorry for the messy writing and the rambling explanation; I'm pretty exhausted and really need to get some sleep.🙂

Thanks for taking the time to read this!

You've already swapped out the power supply and the hard drive, and it's still dead. At this point, you're down to testing a different motherboard. 🙂
If all your hardware is actually functional, installing an OS should be a breeze. Check which CPU you're running, hunt down a used motherboard with a matching socket, and once you swap it in, everything should work fine.
Maybe try some different RAM too, just to rule out a faulty stick.

It looks like the CPU is overheating.
Clean out the cooling system and let me know how it goes.

That’s exactly what I’m worried about, honestly—that the motherboard itself is the culprit. Since this PC is such an ancient relic at this point, if that's the case, we aren't just looking at a quick fix, are we? We'd be looking at a total overhaul: a new motherboard, a fresh CPU, more RAM, and a new GPU just to get back on level ground. It's a bit daunting to think about, don't you think?

I have a nagging suspicion that we might be looking at a temperature issue here, especially since I went through the whole process of deep-cleaning the entire PC just yesterday. Is it possible that things are running a bit too hot despite the fresh dusting?

Just wanted to check back in with you all; I gave it another shot trying to install Windows XP on my PC using her hard drive one more time, and somehow, against all odds, it actually worked. It’s even running fine when I plug it directly into her computer, which is honestly pretty strange since I haven't the slightest clue why it decided to behave this way, but hey, I'm not complaining, right?

Thanks everyone,

I hope I'm not overstaying my welcome here, but would it be alright if I squeezed in just one more question, provided it isn't too much of a bother?

I've been scouring the web trying to track down the drivers for her motherboard, but honestly, I feel like I'm hitting a brick wall because they seem to be nowhere to be found. Have you ever run into one of those situations where everything looks right, yet nothing turns up in a search? It’s quite a frustrating little puzzle to solve.
I've been spending quite a bit of my free time lately looking back at some older hardware configurations, specifically when it comes to those classic motherboard setups involving the MCP68M-M2, and I can't help but wonder if we ever truly appreciated the stability they offered back in the day? It’s funny how we constantly chase the latest cutting-edge silicon, yet there's something almost comforting about the reliability of these older components that just seems to disappear in our modern, hyper-accelerated tech landscape. Does anyone else feel that sense of nostalgia for a time when hardware felt a little more permanent, perhaps a bit less ephemeral than the stuff we're plugging into our rigs today?
It seems like every single Google search I run keeps throwing nothing but results for the MCP6P-M2 at me, doesn't it?
At the very least, I just need to get the internet driver sorted out first, because then I can download everything else directly onto her PC, right? It would be so much easier than this current nightmare where I'm constantly swapping cables back and forth between machines every five minutes, turning them on and off... honestly, it's becoming quite a headache.

Download this or that and give it a shot...