Don’t put WD-40 on the pins. I’d start by pulling out the sicks and cleaning the pins off with a q-tip and iso alcohol. Probably a good idea to clean out the slots now too.
Get Memtest64 and run it with both sticks. If it fails try it with each one by itself. If a stick doesn’t past the test you should be able to get a new one under warrenty. Just start an RMA request and say it failed memtest64.
If its not your ram then its probably a poorly seated CPU. Remove the cooler, clean the paste off and carefully put the cooler back on without over tightening it, or tightening one side more than the other.
Do I know this from Alan Wake 2 or My Summer Car?