Hello. I'm runnng WinXP pro SP3 on an Intel Ci5 2400 box, which I built myself in May 2011 and which has been running just fine until a few days ago. The MB is INTEL DH67CL B3 and the RAM is 4GB Kingston DDR3.
A few days ago it shut down in the night, made a loud siren sound on restart and Windows said it shut down because a thermal event. This has happened a few times since.
The strange thing is the weather is really cooling down here in Australia. All through the hot summer I was file sharing, video editing and compressing and doing tasks which really made the cooling fan sing, but with no problem. The first shut-down was the coldest night of the year, and the computer was just idling.
Anyway, I've removed some dust from the CPU fan and heat sink, and I installed Speedfan 4.47. The CPU is 34c as I type and everything else is in the low 30's except PCH, which is 61c (pic attached).
Last night I left the computer running Windows 7 and it didn't crash, but it did sleep, so that probably wasn't a very good comparison.
Today the computer has been running all day, with multiple apps running and no problem. But the weird thing is it crashes at night or when I am out of the room.
I'm not usually a conspiracy theorist, but it seems strange that this happens a few days before MS pulls support on XP. It's almost as if they've put bugs into the last updates, to force people to migrate to later systems.