defective cpu?or defective oprator?

[Phantom martin]

HELP!!(please)
Just built this rig before christmas...ran ok for a while..did an auto overclock..Bam! core 3 shut down.
Now it keeps freezing up on factory settings and always shuts down core 3 after trying to overclock!
Ran prime 95 overnight,as well as memtest..both came up as a pass..
also ran OCCT,and that said it was ok too.
All temperatures are below 42 degrees,and i only play bf2 bc and browse really,but it still keeps freezing up!Somebody save me please

HIS ATI Radeon HD 5850 iCooler V Turbo 1024MB GDDR5 PCI-Express

AMD Phenom II X6 Six Core 1090T Black Edition 3.20GHz (Socket AM3)

Asus Crosshair IV Formula AMD 890FX (Socket AM3) DDR3 Motherboard

NZXT Phantom Enthusiast Full Tower Case - Black

Corsair HX 750W ATX Modular SLI Compliant Power Supply (CMPSU-750HXUK)

G.Skill RipJaw 4GB (2x2GB) DDR3 PC3-12800C9 1600MHz Dual Channel Kit
Western Digital Caviar Black 1TB SATA 6Gb/s 64MB Cache - OEM

Corsair A70 High-Performance Dual Fan CPU Cooler (Socket AM2/AM3/LGA775/

Samsung SH-B123L/RSBP 12x BD-ROM / 16x DVD Writer Drive

 

[Phantom martin]

Thanks andy, will do that and try again