975x PUE issues with memory

Question

Hi guys,
I have my old 975x running with no problems with 2GB OCZ since a really long time, everything worked smoothly and i never did any OC of any type in the board.
But nowdays 2GB is really few to keep the system and games running with no issues so i decided to upgrade to 4GB, i bought 2 Kingston modules (more precisely this ones -> http://www.ec.kingston.com/ecom/configurator_new/PartsInfo_ar.asp?root=latam&LinkBack=http://www.kingston.com/LatAm&ktcpartno=KVR800D2N6/2G,  but i have encountered problems.
The issue is that when i put the memory the BIOS shows in post 3669952K of memory, witch is roughly 3,5GB, from what i read in several threads about i take that it is a memmory allocation issue that should solve itself once a x64 OS is installed.
But the problem is that when this 4GB modules are installed the board hangs and i cant even run a install of any OS, basically the BIOS posts, i get the "updating DMI pool data..... sucess" then "press any key to boot from CD" and then just a black screen and nothing happens, when i remove one of the modules everything starts to run fine again.
Things i tried:
- Both modules running alone in case one of the modules is broken, both works ok as long as they are alone.
- Another 2x2GB modules (OCZ), same results
- yet another 2x2GB modules (8GB total filling up all slots), and shows 7,5GB and it keeps crashing.
- Every variable in witch i can put 2 modules in the 4 slots.
- Load bios Fail-Safe config, same results
- Load bios Optimized setup, sme results.
I have the 7.1 BIOS version witch from MSI changelog i understand that it should work fine, still, im thinking about upgrading to BIOS 7.9 but i dont know quite how and wanted to ask first if it will solve anything cus i dont want to take the risk if no change would come.
What could this be?
Thanks a lot.
edit:
Here are some caps of the BIOS information tab
and another on post.

Answer 1

Hi jack,
thanks for the reply, i've tried the clear CMOS but none of the 2 methods apply to this MB so this is what i did:
1.- Unplugged power cord and waited about a minute
2.- Press the clear CMOS button SW on the MB, and waited about one minute
3.- Press the power button to be sure as it says on the guide, and waited about one minute
4.- Power on the system.
and this is the other thing i tried.
1.- Unplugged power cord and waited about a minute
2.- Removed the battery and waited about a minute
3.- Press the clear CMOS button SW on the MB and waited about a minute
4.- Reinserted battery
5.- Power on
and then
1.- Unplugged power cord and waited about a minute
2.- Removed the battery and waited about a minute
3.- Reinserted battery
4.- Press the clear CMOS button SW on the MB and waited about a minute
5.- Power on
Same results =(
I tried with 1 or 2 memory modules and the same thing keeps happening, here's a cap of the screen where it gets stucked.
What's with the 1024k OK memory testing? it keeps saying that either i put 1GB or 2GB memory.