OC becoming unstable

Here's the deal. I have had this Q6600 at 3.4Ghz for like 8ish months now and no problems at all. Temps never above 50C even (Thanks to my Dark Knight).

But within the past few weeks I have been getting BSODs in Win 7, about once a day. At first I was just attributing this to it being a beta OS and all, but I have never had these problems before and I have been using 7 since the 7000 build. So I just reformatted today to see if that fixes it at all. Sure enough I got a BSOD about 2 hours into reinstalling all my software.

My next order of business was to check my GPU and Memory. Ran Memtest and stuff and no errors anywhere. So I ran OCCT and ... BAM about 2 min in I get errors in core #0. I have never had that before, I ran OCCT for the full 1hr many times while getting my OC to where it is and I have never gotten that.
Also my temps are a bit higher than usual... 54ish under full load. I know that isnt HUGE but an increase is an increase.

So here is my question... what would cause my OC to become unstable all of the sudden like this? I haven't changed anything in my BIOS really that would affect that.

I am hoping I can just clock it back a bit and it will fix the problem but it worries me that it would just start crashing like that. I will fiddle around with it a bit and see if I cant get it stable again (because I really would like to keep my 3.4Ghz speed). I just hope my processor isn't on it's last leg.