Pc wont boot anymore

Sorry ahead of time for formatting, as im typing this on my phone

Hello, My pc has suddenly stopped booting after i turned it off last night

I have tried:

• reseating the cpu, and applying new thermal paste
• reseating ram, and using only one stick (tried both sticks individually)
• tried reseating gpu
• changing the cmos battery

The pc boots for approx 20 seconds, going to the screen where you can go into bios, but turns itself off before i can get to the bios itself

Now after reseating everything, it is not showing anything on the display anymore

If you have any questions, i will try to provide anwsers