I inserted a Mach Xtreme COPPER MXD3C13332GS (http://http://www.mx-technology.com/en/product/memory3.php?sid=81) RAM into my Intel DP43BFL desktop motherboard. This is a DDR3 2GB 1333 MHz RAM. The computer couldn't start and a "beep, beep, beep (pause) beep, beep, beep, (pause)" sound came out. Then I removed the RAM inserted a Corsair VS2GB1333D3 (http://www.corsair.com/vs2gb1333d3.html?___store=es&___from_store=en) RAM into the motherboard, the computer still couldn't start, and again, a "beep, beep, beep (pause) beep, beep, beep, (pause)" came out. I have installed a proper graphic card (Galaxy nVidia GeForce GT240). I have no idea why the computer couldn't start. Please help me!!! Thank you!