I'd double check your connections on your mobo to see if one of the connectors went loose or got disconnected during your troubleshooting of the boot up issue. I see your memory is rated at 1.9v, so please adjust it in BIOS, if you haven't already. This will minimize any variables in future troubleshooting.
You might also want to swap out the 1 good stick and put in the other stick into the same memory slot to verify that it is good too. It's possible, not likely, that you could've damaged the memory stick when handling it. It's rare, but it's possible too.