Why does my omen show no signs of life?

Around 3 years ago like any other day, I booted up my HP omen 17 laptop with no issues. I used to play heavy games like Fortnite on it. On one particular day, as it booted, I had not yet not signed into my account, the screen started flickering with green and pinkish lines, it dimmed and then it shut off, it never turned on back again.

I have checked the power supply which works fine on another laptop.

There is no smell of any component burned. I took of the heat sink to get a better look at the cpu and GPU which seems totally fine.

When I try to turn it on, only the power button light stays on but nothing happens, there is absolutely no power in the motherboard. The screen doesn't turn on, I don't hear the fans running, one side of the laptop with an HDMI port 2 USB ports and aux ports etc, that side shows no power, while one side does.

I've check the CMOS cell , which is also perfectly fine.

I don't understand that why it just randomly turned off. There was no water damage and it was not hot when I turned it on.

The cpu and GPU are definitely not fried, I suspect that maybe a smaller component might've been damaged but I'm not sure why and how.

Any help would be appreciated.