Many people think it is the power supply if the computer does not start, 
but usually it is something else.  Of course, it can actually be the 
power supply, but when you hear beeping, then that decreases the 
likelihood that it is the power supply.

Here is a link for a simple power supply test.  
http://www.pcpower.com/support/ATX_troubleshoot.htm

If it fails this test, then the power supply is bad.  It could be bad 
even if it passes this test, but the probability is that it is something 
else.

Be very careful not to touch anything inside the computer, and under NO 
circumstances should you get into the power supply, as there are 
dangerous voltages in there!

Unfortunately, there are many things that could cause your symptoms, but 
bad memory or a bad motherboard are the most likely.  Take all your 
memory sticks out except one and see if it starts.  If it does not, then 
exchange the memory stick for another and see if it starts.  If both 
sticks fail, then it is beginning to point toward the motherboard, but, 
as Russ said, the beep code might tell  you what the error is.

Hope this helps!  Good luck.

Dean Kukral

On 6/6/2010 8:37 PM, Jacob Smith wrote:
> i am a 13 year old kid interested in computer sciences,
>
> hear is the problem: we have a computer that we think was wrecked by its external power supply, when we turn it on it sends no signal to the monitor but it beeps at regular intervals. what is the most likely failing hardware? thanks
> jp
>
>
>
>
>    

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