Problems Overclocking

I have having radom reboots after I tried overclocking my computer. It was working fine for a couple of days with several hours of Prime95 stability, but I then tried running memtest86 for stability and ran into a few problems. I worked on moving the memory around until I got full memory stability for over 8 hrs. After I got memory stability I started getting random reboots once I was in Windows 7. I got to looking at my voltages and I noticed in CPU-Z it show my CPU voltage between 1.36 and 1.376, but I have it set at 1.4 in the bios. Could this be part of the random reboots in Windows? Below are my system specs please let me know if you need any more information.

GIGABYTE GA-EP45T-UD3LR

Intel Pentium E5300

OCZ Obsidian 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600

Seagate Barracuda 7200.12 500GB

OCZ StealthXStream OCZ700SXS 700W

Antec Three Hundred Illusion

POWERCOLOR HD 4870 1GB

I just tried uping the voltage 1 more notch and my voltage is still at 1.376. My main problem is when I first open windows it restarts 3 or 4 times before it is stable enough to run for a little while. I only have this overclocked to 3.0ghz currently. I had this stable tested at 3.33ghz before. Do you know what I should try testing first? (motherboard, memory, powersupply)

Q6600? I thought he had a Pentium Dual E5300?

I have another update. I can get my computer to run at 3.5 ghz with stability when I put one stick of memory in, it does not matter which one they are both stable. When I put both sticks of memory in, it doesn't matter if it is in duel channel or single channel. Would this mean I have a memory problem or a motherboard problem?

I am running on a single memory stick right now at 3.5 GHZ (333mhz x 10.5). I took the memory multiplier off Auto and set it to 4.0B? (the one for 333 fsb). The memory runs at 1333mhz. My memory is listed to run at 1600mhz.