Hi all. Maybe there is a guru here who has run across this before, or has an idea of what the issue is. So we have a 2009 15" MBP (A1286) c2d 3.06GHz model....it came to us with only 2GB (2x1GB), which is odd, as it came from the factory with 4GB (2x2gb) for this bto/cto model. Very oddly, we have tried 10 different sets of RAM in it...all known working, some directly out of other working Macbooks (2009/2010), in either 4GB (2x2gb) or 8GB (2x4GB), in either pc3-8500 or pc3-10600, hynix, samsung, etc......Every single combination has only produced the "beeps" (bad ram). UNTIL, we tried another set of 2GB (2x1GB)... This is the first time we have ever run into or heard of anything like this...we are totally stumped.... So to recap, someone downgraded this seemingly mint/untethered machine to 2GB (2x1GB) of RAM and it coincidentally will not accept anything over 2GB of RAM..... FYI, we have SMC reset and PRAM set. We've tried single modules only, and in both slots. We have run out of any idea of trouble shooting. The machine works well with 2GB of RAM (but bogged down in Yosemite of course). But it is very odd. Any ideas anyone? Thanks in advance!