How to fix beeping Mac mini (2009), not detecting RAM. | MacRumors Forums
Amazon.com: Timetec 8GB KIT(2x4GB) Compatible for Apple DDR3 1333MHz PC3-10600 for Mac Book Pro (Early/Late 2011 13/15/17 inch), iMac (Mid 2010, Mid/Late 2011 21.5/27 inch), Mac Mini(Mid 2011) RAM Upgrade : Electronics
SOLVED: Beeping sound after upgrading RAM. The old RAM work fine. - MacBook Pro 13" Unibody Early 2011 - iFixit
How to fix a MacBook beeping or Ram not detected - YouTube