I'm by no means an expert but this may be worth sharing.
A couple of years ago I bought a brand new Dell PC. After only a couple of weeks we experienced a number of crashes. Intiatially Dell were adamant that it was a software issue, but to cut a long story short, when an engineer finally came out to the pc, he found that a fan within the computer was being obstructed by a mis-routed cable. The PC would stay on just so long and then overheat and shut down..