Computer freezes at random while playing games

[Ex7ra]

Now, before I move on, here are my specs...
I5 2500 3.3ghz quad core
Gtx 560ti GPU
Asus z77 motherboard
2x4 GB vengeance ram
XFX 650w Psu
When gpu load is 100%, it runs at 75*C

Tl;dr : comp freezes in games, ctrl alt del does t even work... No case fans and only stock CPU cooler

Okay, as the title says, I'm freezing while gaming... The first time that this happened i was on bf3, all settings max off, and y while system just completely froze, ctrl alt del didn't even work, hard reset was needed.
The next time it happened I was on call of duty 4, loWest settings possible and the same thin happened, after the reset in wen back on to play with my mates again and after about 10 mins the same thing happened again... note that before this I was on arma2 for about 3 hours with no issues

I think that this might be a heat issue because the case that I'm using at the moment doesn't have any fans on it at all... Only the stock CPU cooler is on there at th moment.. I have just built this system and I have no other ideas what it causin it, do any of you have an idea?
Please excuse the typing, I'm on my iPod at the moment

 

[knightdog56]

Might be memory setup in BIOS, Check memory to see if it is a match in the BIOS if not set to memory specs.

 

[geekapproved]

You THINK it might be a heat issue.....yet you haven't even told us what the cpu temps are........

If you tell us what the temps are, we could tell you if it's a heat issue. lol

 

[10pies]

Yeah thats what I was thinking. Maybe your fans stopped working or something like that?

 

[Ex7ra]

Is there a program that records CPU temp to a file, as I can't alt tab when it freezes, as completely nothing works.

 

[Herr_Koos]

CPUID HWMonitor or Piriform Speccy.

If the CPU is overheating, it will happen quite quickly. Alt-Tab out of the game before it freezes to check the temps.

And yes, you will need to get some fans for that case.

 

[Ex7ra]

I was trying to record my CPU temps, it locked up in game like it did last time, only this time, after reset, it won't turn on again, you can hear the fans on the heatsink and Psu going, but nothing happens on the screen and there is no lights on my mouse or keyboard, is this still a CPU issue?

 

[Ex7ra]

Can I bump? Just blew £400 on these new components and am feeling pretty sad at the moment...