In case you are not aware the two blue slots are recommended to be used when OCing.
Clear the CMOS following the steps at the attachment below.
Test one stick at a time as detailed below;
How to physically test your Ram.
The following checks require the computer case to be opened so take the following
safety precautions 1st, disconnect the power cord from the wall socket and take anti static
precautions before touching anything inside, you can do this by touching a bare metal
part of the case.
Have a pencil and notepad to hand.
Remove each stick of Ram and blow out the memory slots.
Insert the first stick of Ram in memory slot one, reconnect the power and in the case of a desktop computer the video to screen cable.
Power up the computer and see how it goes.
Make a note of the results.
Repeat the procedure until the first stick of Ram has been tested in each memory slot and the results written down.
Remove the first stick of Ram and put it to one side on top of a piece of paper with the number one on it for identification purposes.
Repeat the procedure with all Ram until each stick has been tested in all slots, the results written down and the sticks identified numerically.