I'm upgrading the RAM in my late-2009 (October 2009 build date) Mac Mini from 2GB to 4GB. I ordered a Patriot Memory 4GB (2x2GB) RAM kit from Newegg, and it arrived over the weekend.
I just installed it, and when I attempt to boot, I get three beeps, along with a corresponding flashing light on the front, and it won't boot. I powered it off and researched it and determined that the RAM banks failed the memory testing during the Power-On Self-Test. I've submitted a RMA with Newegg to get a replacement.
Any tips for me if the replacement RAM also fails?