"Dave Baker" wrote in message
...
As what?

It doesn't switch off at a particular point in the boot sequence which
might point at a software thing.

Ah, I see.


Any guesses? I've got AVG free installed and that shuts it down after
doing its tests. That sequence always works ok.

If it only shut down after running AVG then we'd be fairly safe in calling
it a software fault but as it also does this during boot up then it's more
likely hardware. My first call would be a faulty RAM stick which only
manifests when particular sectors get used and also after running memory
intensive software such as AVG. Try removing, cleaning and reseating the
sticks and also running a RAM checker such as DocMemory. If you have any
swap the sticks for known good ones or even just remove one at a time and
run the machine with limited RAM until the problem manifests again.
--

Uninstall AVG or disable it at start-up. I've come across this very issue
before on another PC. Unfortunately I don't recall exactly what the problem
was with AVG but IIRC it was due to an upgraded version. I have no issues
with AVG in general - I use it myself on a number of PCs with excellent
results - but there is a certain problem identical to yours being manifest
on some machines.