I have a Phenom 955 BE which one day one of the cores just died in. It would get to the BIOS screen then just fall over. Took ages replacing everything assuming CPU is least likely but in the end as a last resort I shut off cores one by one in the BIOS and found it. Have run it on 3 ever since with no issue.
I know you can't get into you BIOS but just goes to show it can happen.
I know you can't get into you BIOS but just goes to show it can happen.