Help Trouble Shooting a PC that won't start - 500 points

I have a Sony desktop that won't start.  When you turn it on, the light comes on, the keyboard lights flash but nothing else happens.  I opened it up and verified that the fan is running so it seems like it has power.  It never displays the startup sequence on the monitor (i.e. checking RAM, etc.).  Nothing displays on the screen.  Could someone point me in a direction of what to try next?  I'm wondering if somehow the motherboard went bad and if so how can I verify it?
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phototropicConnect With a Mentor Commented:
If it's a Sony Vaio, you may have problems sourcing a new PSU.
Here in the UK Sony will not release PSUs to any outside engineers, and as you have mentioned, the unit is a non-standard size. The last time I tried to do this for a client, I had to register the computer with Sony, who gave me a magic registration number. Only then could I talk to tech support, who cheerfully informed me that the best they could do was to sell me a power cord!
In the end the client had to telephone Sony and book an appointment for an engineer to call. He then took the pc away for a weeik, and then brought it back with a new PSU fitted. I did not have the heart to ask how much this whole procedure cost...
MarkConnect With a Mentor Commented:
There is the posibility that the power supply is the culprit, even though it is turning fans. If there are no beep codes coming from the board I would replace the power supply. If that doesn't get it going to at least a beep code then the motherboard would be next on the list.
Short-quick beep = VGA problem
Long beep = RAM problem
No beep = Motherboard or processor problem.
1. Don't be upset yet. Try to reseat your RAM/Processor/IDE cables.
2. Reset the BIOS by shorting the CMOS battery or remove the CMOS battery for a while.
If everything above does not solve the problem, check the motherboard for bad capacitor. All capacitor cap should be flat and not rounded.

Good luck.
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The best way to verify the problem is to try startup with the bare minimum.

Remove all cards and drives, leaving a power supply connected, motherboard, cpu/fan, 1 stick ram, video (onboard, if available) and monitor.
If you get nothing (no beeps/no video), it's wise to test your components in a compatible system to verify each one is good: ram, cpu, video (if not onboard). It is not wise to test new components in the possibly faulty mobo, as it can possibly fry the components. It's better to test your components in a good machine.

If you get them (with your sony model#, as well).

If components are verified as good, and your setup does not start, you are left with: power supply, motherboard or possible short.
To test for a short, remove the motherboard from the case and place it on a non-conductive surface like cardboard, try to run again with the bare minimum.

Check the motherboard for leaking or bulging capacitors..a sign the board is done. example:
Try swapping out the PSU with a known-good power supply. If the same...the motherboard is the culprit.

If you were able to post with the original barebones setup, begin replacing your components, one at a time (system off/unplugged) to identify if another component is to blame.
dyaroshAuthor Commented:
I'm beginning to think that it is the power supply causing the problem.  Now my problem is trying to find one that will replace it.  My local computer store has a comparable unit but it is not in the dimensions that I need.  The power supply to be replaced is 10 cm wide and 16.5 cm long.  Can anyone recommend a good site for me to find a replacement power supply?
Last one I bought came from Newegg ( They also have user reviews which may help your buying decision.


We need the model of the desktop to narrow down the field . There is always the possibility that there may be a propriatory PSU in that Sony. Until we get the model# we can't tell you .
I thought the question was "Trouble Shooting a PC that won't start" Although I agree, phototropic deserved points for his answer, the fact remains, the indication of the PSU being the problem was brought to the askers attention in the very first post. The question of how to source the PSU was secondary to the original, hence phototropics points.
sparkmaker is quite right.
I came to the question after a number of experts had already posted, and responded to dyarosh's request for information about sourcing a replacement PSU.
dyaroshAuthor Commented:
My apologies.  You are quite right.  I should have split the points with 400 going to sparkmaker and 100 points going to phototropic.  I was too quick on the draw when I awarded the points.  I will contact the moderator to see if I can have the question fixed.  Again, I am sorry.
Not a problem, the question should remain open until you can catagorically determine that it is in fact a PSU issue, otherwise it could mislead others who read the posts if it isn't the problem. Could you post your model and serial number for this sony. That way we an continue to look for a replacement along with you.
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