Did you manually set the RAM timings and voltage to the manufacturers specs in the BIOS? That RAM is rated for 8-8-8-24 timings at 1.65v. You also may have a bad stick of RAM. Start off by setting the RAM to specs. If it still doesn't work, you'll have to try each stick of RAM individually to try to find the faulty stick. Did you read the checklist posted above? It goes through all this plus a lot more.