Question Error code 51

[zorrrro]

Hi
Built a system using a second hand motherboard but everything else new.
Worked great for a week than on a reboot code 51 appeared which is something to do with memory but my Ram sticks are brand new.
Took it to a store and they worked on it but no joy. CPU was reseated as well

Is the motherboard dead? I'm not sure what to do from here. Any advice?

 

[Lutfij]

When posting a thread of troubleshooting nature, it's customary to include your full system's specs. Please list them like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
Chassis:
OS:
Monitor:

Include all parts that were recycled and all parts that were purchased brand new. Please inspect the CPU socket for any bent or broken pins.