I would start by suspecting overheating. Try cleaning the dust from all 
external fans and the case filter, if applicable. If you are comfortable 
inside the case (  take precautions against static electricity by at 
least touching the case often), you can check and clean internal fans 
and heatsinks.

While you are inside the case, check the connections of the hard drive 
data cable.

Another possible cause, although it does not explain closing down while 
the computer is already working, is that the hard drive is not getting 
up to speed ( spinning) fast enough for the initial start up. I have not 
heard of this situation in a long time. Just a thought.

Also, check your power settings and set them to not allow "hibernation". 
Sometimes a computer does not handle hibernation very well. However, 
this does not explain the start up problems.

I hope this helps.

Tom

JST wrote:
> When I start my computer, it suddenly shuts down in the process. Then 
> I try it again couple of time, then it works. I keep it running all 
> the day. Only once or twice it also closed when it was on and i went 
> to take my lunch .that happened only twice in the last month, but 
> problem at the start is almost daily now.
>
> Is it power supply or my hard drive coming down or my power conection 
> ? something is wrong somewhere, plz advise
>
> I m running XP with sp2 installed, Ram is 2 gig, HD is 160 gig, a 
> fairly new machine
>
> Jagpal Singh Tiwana
> Dartmouth, Canada
>
>               

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