OK, I had several days without mishap..
Now it's on again! This time it happened while browsing photos on Facebook using Chrome.
This is the WhoCrashed report:
On Sat 21/09/2013 10:32:34 GMT your computer crashed
crash dump file: C:\Windows\Minidump\092113-21122-01.dmp
This was probably caused by the following module: ntoskrnl.exe (nt+0x4ADE7C)
Bugcheck code: 0x124 (0x0, 0xFFFFFA800431D038, 0x0, 0x0)
Error: WHEA_UNCORRECTABLE_ERROR
file path: C:\Windows\system32\ntoskrnl.exe
product: Microsoft® Windows® Operating System
company: Microsoft Corporation
description: NT Kernel & System
Bug check description: This bug check indicates that a fatal hardware error has occurred. This bug check uses the error data that is provided by the Windows Hardware Error Architecture (WHEA).
This is likely to be caused by a hardware problem problem. This problem might be caused by a thermal issue.
The crash took place in the Windows kernel. Possibly this problem is caused by another driver that cannot be identified at this time.
Also attached the Temps screenshot after the restart..