Then we might have to look afield for something else. Did you clean the slots? I cannot remember referring that so take a look at my ditty.
SLOT CLEANING
Now as for the slots to clean them use a strip of old credit card (or any card thin enough some are better than others ) about 1/2 inch wide nip the corners off one end - preferably round them offhold a piece of thin lint free cloth over the end dab on some form of alcohol - isopropyl alcohol (what we swab the skin with before an injection) is good and GENTLY swipe along the slots.
This can also be done for the GPU slot/s and also the contacts of the sticks or cards - not the stick but some lint free cloth of course. See my pic for the sick but please be very gentle doing it if you are in any doubt - please ask before doing it but I use this all the time and have yet to damage anything.