After trying each stick solo, try each DIMM solo to make sure each is working.
If the board fails to boot with a single stick in an particular DIMM, remove the mainboard from the case and inspect the CPU socket with a bight light and magnifying glass. ...
If the board fails to boot with a single stick in an particular DIMM, remove the mainboard from the case and inspect the CPU socket with a bight light and magnifying glass. ...