I had a stick of RAM go bad so i removed 1 of the 2gb sticks and left 1 in and everything worked fine but i wanted more RAM but didnt have a whole lot of money so i bought pny 4 x 4gb ddr3 1066. when i have all 4 sticks in the computer wont boot but when i only leave 1 in the 1st slot of the second channel everything is fine. when i put a second stick in the 2nd slot of the 2nd channel i get blue screens when i put any in the first channel it doesnt boot. im thinking its my motherboard. but im young and havnt gotten very good at troubleshooting computers yet