My computer won't boot

[Curesto]

Hello there. I have an old computer. It was working perfectly fine until last month.

After pressing to power button system turns on for 5 seconds and suddenly shuts down and starts running again but never posts.

For troubleshooting i have tried these:
1)Tried booting with different CPU
2)Tried booting with different GPU
3)Tried RAMs on different slots
4)Tried every single RAM
5)Tried PSU on different system. Works perfectly fine.
6)Checked if there's something that can short the motherboard.
7)Cleaned the system
8) Tried CMOS reset

None of them worked. My bet is motherboard is dead but i'm not completely sure.

If it's required, system specs:
CPU: Intel Xeon X5450 C0 3.00GHz
Motherboard: ASUS ROG Commando
GPU: AMD Radeon R9 280X 3GB GDDR5 384-Bit
RAM: 6GB DDR2 800MHz CL6 Kingston (1GBx2 2GBx2)
HDD: Samsung HD250HJ 250GB 7200RPM
PSU: Gigabyte P650B 650W 80+ Bronze
OS: Windows 11 Pro 64-Bit

All the fans work perfectly fine.

 

This motherboard has "post check" screen that shows which hardware is checked while booting but it's stuck at CPU INIT since this issue.

 

Is my motherboard dead? If it's dead, it's not a problem the replace it as LGA 775 boards are cheap.

[Fl0yd-]

try a different cpu power cable, could be a power delivery issue

[Levent]

Killing a CPU is hard, you would have to run it hot for a while. RAM would be my suspect.

[SavageNeo]

could replace the cmos battery, they have a lifespan of 5-10 years, if i remeber correctly. CR2032 is the battery, used in many flashlights etc, coudl buy 10 for 1 dollar

[Curesto]

None of them worked. I will replace it with Gigabyte P35 motherboard.

[Curesto]

This all started happening after plugging dead HDD on computer. And after this motherboard refuses to giving post.