It is such a strange behaviour on my Acer Aspire 5720 system running Windows Vista Italian version.
I have been using my laptop for a year and recently it often shuts down immediately without displaying any message. I discovered that the CPU is too hot, the CPU fan is not spinning when Windows starts, but the interesting thing is that when I just turn on the computer with the Power button, the fan spins well, only after 2 seconds, when Windows Vista is launched, it's time for the CPU fan to stop.
I wonder what happened?