In article ,
George wrote:
Have you got the fan the right way round? ie the cool air from the
fan should blowing onto the heatsink,also check the heatsink fins
for dust clogging them?

Heh heh. It mysteriously turned itself round?

Well it worked for me because the last time I cleaned this computer out
(if only dust was a comodity I'd have been rich) I put the fan the wrong
way round and was getting exactly the same symptoms you're faced with.
After much head scratching it suddenly dawned on me that the cool air
from cpu fan was blowing outwards,a quick change around and we were back
to normal. Funny though I have two big fans in the case one on the front
chassis metal for blowing cool air around the other fan on the back of
the chassis for drawing out any warm/hot air.

The symptoms only started after about a year of it working perfectly.
That's why all these suggestions of poorly fitted heatsink or fan etc
don't cut much mustard with me. Plus the fact it now happens so quickly -
within a minute or so of switching on from cold.
I got this reply on a RISC OS group (I asked for a more suitable
newsgroup) where they are understandably iffy about PC posts :-

*********************

I had a similar problem. I think it was a fault in AsusProbe reading
the temperature wrong & shutting down as an emergency. Probe V2.24.10
works ok but I am not entirely sure it wasn't another monitor??

**********************

but no reply to an email asking for clarification as I don't really
understand the solution if any.

--
*I didn't drive my husband crazy -- I flew him there -- it was faster

Dave Plowman London SW
To e-mail, change noise into sound.