Question New working system, suddenly no post, display, or beeps.

[MarkJohnson]

I put a new rig together for a friend. He has been using it for two weeks. Suddenly the system won't boot. He brought it back to me,

I turn it on and no error code beeps at all. no even the good post single beep.

The CPU fan turns on/off over and over like it's trying to boot. The rest of the fans and LED lights are on continuously.

Did the CPU go bad? How can I tell for cure? or something else? My return windows is slowly arriving for replacement.

EDIT:

Things I've done so far:

Reseated the memory
Clear the CMOS
Removed battery, short the battery contacts for a full minute, and clear cmos again.
I tried both HDMI cable and DP cable.

Not sure what else to try without removing everything and putting it on the bench.

 

[rgd1101]

full system spec? include make and model of the psu

 

[MarkJohnson]

full system spec? include make and model of the psu

Ooops, I forgot:

MB: Asus Prime X470-Pro latest BIOS.
RAM: Corsair Vengence RGB (CMW16GX4MM2C3200C14)
CPU: AMD Ryzen 7 3800X
PSU: Seasonic X650 80PLUS Gold (SS-650KM)
GPU: Zotack GTX 2060 6GB (ZT-P10620A-10M )
SSD: Samsung 970 Pro 512 GB (MZ-V7P512BW)

 

[rgd1101]

check the cpu for bend pin. redo the thermal paste

 

[MarkJohnson]

check the cpu for bend pin. redo the thermal paste

Already did that, and same thing. Since it was working for two weeks, it doesn't seem that could be the issue anyway.

I called Asus for board replacement. No one is working and had to go through troubleshooting guide and file rma and it said my MB already had an RMA? It said it would notify me by email for next steps.

This is going to take forever.

 

[MarkJohnson]

OK, I was reading on forums and seen a no ram at all should give an error first. I removed my RAM and bingo. 1 long beep and 2 short beeps. Getting closer.

EDIT:
OK, error code means no memory. I tried a single generic DDR4 2133 memory and cleared the cmos. It still does the same thing.

So if the motherboard is beeping for memory missing, but no beeps or progress for over two minutes with memory back installed, then the CPU is bad?