Computer freezes every few minutes

Hello there everyone,

My PC has been freezing for a couple of days now after about 5 Power Cuts occured, though I do have a basic surge protector. It keeps freezing every four minutes or so. For example when I'm playing ArmA II the game freezes, but I can still hear people's voices over ventrilo and I can use the push to talk fine. When I'm watching a video using Windows Media player, the video and the audio just completely freeze then the audio cuts in and out, followed by the video playing normally again for a couple of minutes. Another example is when I'm browsing;the browser just outputs "Not responding" and when I try to open task manager it stalls until the issue passes then the manager pops up.

Computer Specs:
CPU: Intel i5 2500k
RAM: Kingston PC3 10600 CL9 240 PIN DIMM - 2 Sticks, one 4GB and one 2GB-Total: 6 GB.
Motherboard: Gigabyte Z68AP-D3
BIOS: Touch BIOS Award Modular v6.00PG
Video card: nVidia GTX 560 Ti ( Gigabyte version )
PSU: 500W HEC 500 TE 2WX
OS:Windows 7 Ultimate SP1 64 Bit

I've ran chkdsk twice, no bad sectors or so. I switched out RAM slots, and removed the 2GB stick completely but the issue still persisted, I didn't want to remove the 4GB stick and try the 2GB one because I'm running Windows 7 Ultimate. The freezing also happens when I'm browsing, PC just freezes momentarily for a period of about 40 seconds and then runs perfectly fine for 4-5 minutes.

I also did a system restore to a point before the freezing occured; It did not work.

I ran memtest86 on each of my sticks separately for 7 passes, no errors.

More info: The PC can boots up nicely, and fast, However; The issue happens about 10 minutes after booting up.

I went into BIOS and checked my voltages:
Vcore: 1.212V
DDR15: 1.524V
+12V: 12.024V
VCC3: 3.324V
VTT: 1.064V

but according to CPUID/CPU-Z when I start up the voltage of Vcore drops down and variates from ~0.800 to ~1.200

I'm about to run BurnIn test and post the results here.

 

What checkdisk did you run?

chkdsk /f /r

That will check the disk surface.

Hard disk is my bet at the minute. What make disk is it?