Ok for the heat sink, I will check tonight if it is not shorting out some components behind the motherboard. I believe that when I bought my components the guy mount my cpu/motherboard/heat sink set. So i didn't do it myself and also that he did not put the little plastic rounded things to support the blackplate, so this is a lead, I'll tell you that this evening.

Another clue, I've noticed that by letting the ram at 1,5 vdimms on 8-8-8-21 @ 1523 mz I had less detecting issue on reboot. If the computer was completly started to windows and reboot the ram was detected whereas if I do a "ctrl-alt-sup" during the bios post , the ram was detected as 4gb...
Actually i've never tried this voltage, I have always put 1,6 minimum. So i believe the ram (or cpu) don't like this extra-juice.


Now about that :
"You said that if using only one ram stick some times result in no boot, is this with on spesial ram stick ore slot, ore dos it happen wit any stick/slot."
It happen with any stick or slot, so i believe it is not a motherboard or cpu issue.

About the highlighted stuff:
"Inspecting the memory settings inside the BIOS suggested otherwise, giving us the ability to set latency timings for each of the three modules. Here was another clue: the third module could only modify the CAS latency, while the other settings were unavailable."

I do not get it, I mean, During the post, if I see that there is only 4088mb detected I go in bios and of course it only report 4gb , also i don't know how to set latency timings for each of the three modules, I'm only able to set the timings for all the sitcks, not one by one.

about this : Visiting the Windows Resource Monitor delivered another valuable clue: 6144 MB of memory installed, but 2050MB was Hardware Reserved.
---->I've never see those kind of informations in windows resources monitor.

When I said " I doesn't even post" it means that the bios is not posting so I can't get into or in windows.

Sorry for my bad english, and thanks for your time.