Failed OC now freezes at stock

[Serberrus]

Hi, I recently attempted to overclock using a lot of guides including the one on this site and many others like those on overclock.net and many others. I cranked it all the way up to 1.395v to try to get it to run but it would consistently crash in less then 20 minutes. I couldn't get my computer to be stable after many many tries, it seemed strange to me since many of the posters were saying the 2500k would go to 4.5ghz with little to no voltage adjustment. Now my computer wont survive more then 30 seconds of stress test without crashing, Ive reverted to default settings through the bios, and used my reset cmos button. Thanks in advance for the help, I really hope i didn't break something. PS. My cooling was fine, i didnt go over 65 celsius on all but one core. Again thanks.

Programs used:
OCCT, Prime95- Stress testers
CPU-Z- Monitor software
Realtemp

Specs:
i5-2500k
asrock extreme3 gen3 mobo z68
msi twin frozr II gtx560 ti
Mushkin 1000W non-modular psu
8gb crucial balllistix RAM
Hyper 212 cooler
NZXT phantom

Update: I used memtest, not the one you boot just the one you use on your desktop, and it crashed (I had to use 4 memtests at 2gb each to get it to work) does that mean its definitely my memory? I'm going to grab a flash drive on the way home from work and attempt the boot memtest and see what that says.

 

[amuffin]

Change to default bios settings, if not clear cmos, if not reseat cpu.

 

[Serberrus]

Ok ill do that when I get home and update what happens.

 

[Serberrus]

So before I took everything apart which I really didn't want to do. I used memtest and it turns out I have 1 bad stick of ram (2x4gb) and after taking it out and putting the good stick in the first slot, I passed memtest and from there I logged on and stress tested my CPU which it passed for 8 hours, so I'm going to attempt a overclock again and rma my ram and see if everything holds up; thanks for the reply muffin!

 

[Serberrus]

Best answer selected by Serberrus.