Post code 53 is related to memory, this code can be caused by memory that is not seated or not installed.  Please verify memory is installed until both side "click" and the retention tabs move inward. 

If the issue persists, test a different DIMM in the slot, or try both DIMMs in a different slot to isolate the issue to a DIMM issue or a slot issue.

Also always ensure that the memory is installed into Slot 1 first.