Hello, I decided to upgrade my ram in my dell optiplex 745 sff pc, The ram fits in the slots perfectly and it matches the other ddr2 ram thats in the computer, 667 mhz and each stick is 2gb, There is already 4 gb and I added 2 sticks correctly, i have constantly reseated the ram and the computer originally made a beeping sound, Now all I hear when I start the computer is the fans whirring and it is no longer booting up, The ram is the right one and is the exact same one as required in the computer