how do i test for a bad memory slot ?

Bottom RAM slot not working in mid-2010 mini ram slot 1 and 3 or 2 and 4 Note a little more testing today shows that it works with RAM in 1 & 2 Or just 1, or just 2 I had been trying for 1+3 or 2+4 to get dual rambo slot wallet put RAM only in Slot 3 and try it I suspect all of the slots will work alone, due to SamForbis' answer below Knowing Slot 3 is trouble

rambo 789 slot 48 and every time there is somethinganything plugged into the right slot, the laptop throws the 3+2 light code on Caps Lock With the right