Just to provide us with more information, can you please post screenshots of what CPUID
shows on the important tabs: CPU, CACHE, MAINBOARD, MEMORY, and then SPD for each of the four DIMM slots (I assume all four DIMM slots are now in use).
You say you have the original 2x2GB cards, as well as the new 2x4GB Kingston cards. Are the originals plus the new ones matched? We'll see from the CPUID images, but were the "gift" cards designated specifically by you as to part number for compatibility in your machine?
Also, if you run Taskmgr and click on the Performance tab and then push the Resource Monitor button and then select the Memory tab and look at the bottom of the screen to show the Physical Memory layout, what does it show (screenshot please?)?
On my 4GB machine (with 1GB ATI HD4850 video card) I show virtually all 4GB as "available". But I show essentially zero as "hardware reserved". What is "hardware reserved" on your 12GB machine? This is BIOS-related, and is tied to the hardware you have in the machine. What is your video card? Any other expansion cards?
(a) From Aida64 (used and free add up to 4GB):
(b) from Taskmgr (in-use and available add up to 4GB):