I recently upgraded my pc's ram and when i install a GSkill Ripjaws DDR3-1600 into the motherboard,the other ram (MPPU2GBPC1600) got disconnected from the motherboard.Both of them are 2gb so i should have 4gb but the task manager and other system thing just said that it is 2gb and my ram frequency went from 1600mhz down to 1333mhz.But the CPU-Z said that i am having 4gb of ram but it said i am using single channel.Can someone explain this?I just trying to upgrade my mother's old computer