3700x not posting, MB red CPU LED showing

[Squibbies18]

So, a few weeks ago I helped a friend assemble their new ryzen 3000 rig. The build went smoothly and everything worked fine. A few days ago my friend was trying to add a SATA SSD to their rig and because of the case layout they had to remove the motherboard first to add the new SSD. After everything was plugged back in the machine no longer posted and the red CPU LED light was showing I wasn't there when he was doing all this so I don't know exactly what happened. (Motherboard is the ROG strix X470-I gaming). We tried putting the CPU into a an x570 asus prime board and while no diagnostics lights stayed on it still didn't post. My friend did try returning the CPU to the retailer but according to them the CPU works fine so now. I have a few theories of what to try (which I'll list down below) but I wanted to see if you guys had any ideas as to what It could be or any suggestions on what to try next. Thanks in advance!

 

• Could be a RAM issue, might be worth swapping a RAM sticks to see if one of them has failed
• Could be a BIOS issue, maybe the BIOS has gone corrupt and now is no longer detecting the CPU correctly 
• might of accidentally bridged the CMOS flash pins so the BIOS has reset
• Could be a motherboard issue, maybe there's been an issue with the socket?

[Stormseeker9]

I would try and see if a BIOS flash solves the issue.

[lavacandy]

try reseating ram 

[Squibbies18]

26 minutes ago, Stormseeker9 said:

I would try and see if a BIOS flash solves the issue.

I would but the machine isn't posting at all and his Motherboard doesn't have any kind of BIOS flashback feature

[lavacandy]

or take the battery on the board out and then put it back in after 30 sec 

if that doesnt work make sure your storage is in the right connectors if that doesnt work boot your pc and leave it on for 1hr if all that doesnt fix the problem then it would be a board or cpu 

[lavacandy]

do u have discord i can help you while talking