[Need Help] Computer Problem [Please Read]

Well, I built computer about a year ago (maybe longer), and it is great in my opinion. I started with 2gbX2 ram (totaling 4gb). Then, I bought 2 more 2gb ram sticks, so I could have 8gb total. My motherboard supports it, but the problem is it I add one or more of the sticks (totaling 6gb or 8gb), my computer won't even start.

I checked all the ram, and it isn't a problem with the ram. I took the 2 that I were using, and I replaced them with the 2 new ones, and it worked. It just won't turn on if I have more than 2 ram slots filled.

My specifications for my computer are as follows:

CPU:
AMD Phenom II X4 965 Black Edition Deneb 3.4GHz 4 x 512KB L2 Cache 6MB L3 Cache Socket AM3 125W Quad-Core Processor HDZ965FBGMBOX

GPU:
SAPPHIRE 100283FLEX Radeon HD 5770 FleX 1GB 128-bit GDDR5 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Video Card with Eyefinity

RAM:
G.SKILL Ripjaws Series 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) Desktop Memory Model F3-12800CL9D-4GBRL

PSU:
CORSAIR Enthusiast Series TX650 V2 650W ATX12V v2.31/ EPS12V v2.92 80 PLUS BRONZE Certified Active PFC High Performance Power Supply

MOBO:
ASUS M4A79XTD EVO AM3 AMD 790X ATX AMD Motherboard

Edit:
Here are some more specs of my computer just in case you need them.

Case:
COOLER MASTER HAF 912 RC-912-KKN1 Black SECC/ ABS Plastic ATX Mid Tower Computer Case

Monitor:
ASUS VH242H Black 23.6" 5ms HDMI Full 1080P Widescreen LCD Monitor 300 cd/m2 ASCR 20000:1 (1000:1) W/Speakers

HDD:
Western Digital Caviar Black WD5002AALX 500GB 7200 RPM 32MB Cache SATA 6.0Gb/s 3.5" Internal Hard Drive -Bare Drive

DVD Reader/writer:
HP 24X Multiformat DVD Burner 24X DVD+R 8X DVD+RW 12X DVD+R DL 24X DVD-R 6X DVD-RW 16X DVD-ROM 48X CD-R 32X CD-RW 48X CD-ROM Black SATA Model 1270i LightScribe Support

Any other information that you may need, please don't hesitate to ask.

PS: I called ASUS, and told them my problem, and they said that not one person has had a problem with more than one slot on the motherboard, so they don't think it's a problem with the mobo.

 

Check the ASUS download site to see if a BIOS update is available for your board. If so, install it using EZ-Flash. Although most BIOS updates don't specifically list memory issues, I had a BIOS update solve problems like this more than once.

Hope this helps.