Power problem or possible virus?

[Benado1]

Hello. I am submitting this post on behalf of a friend as she has no computer access. Her computer was running fine when her son was playing a racing game online and then it just turned off. Since then there appears to be no power to the CPU. She called the internet provider tech support and they offered it sounded like a power problem rather than a virus. Any ideas?
She tried a new power source and still no luck. I was wondering if the fan blew...but I'm not sure if that would prevent the computer from even turning on. Sorry for the simplicity of this post, but I don't know any specifics...yet.
Thanks

[Sylvander]

Download a copy of my diagnostic flowcharts from here
www.erniek.eclipse.co.uk/downloads/sylvanderdiags.zip
and print them to leaf through.

Begin on the START UP chart.
1. Are there really no signs of life whatever?
No LED's glowing, fans spinning, or sounds?
If so, the PC is "dead", go to the SYSTEM chart.

SYSTEM
2. The PC appears dead and the PSU fan is not running.
Check the PSU voltages as follows:
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TESTING ATX POWER VOLTAGES

See this http://www.pcguide.com/vb/showthread.php?s=&postid=152496#post152496

Black = ground
Red = +5 volts
White = -5 volts
Yellow = +12 volts
Blue = -12 volts
Orange = +3.3 volts (?)
Green = power on

Turn the power on. The fans should at least come on so that you know you have power.

Turn on the voltmeter and set it to measure DC voltage. Start with an IDE power connector that is not used. Place the black lead of the voltmeter in the hole of the connector that has a black wire (ground). Connect the red lead of the voltmeter first to the yellow hole and then to the red hole. The voltmeter should read +12v and +5v respectively.

The other voltages may usually be measured at the motherboard power connector by simply sliding the red multimeter test probe down the hole where each colour wire goes (with the black probe connected to any black wire as before). Really you only need to check the orange wire for 3.3 volts at this connector. If +12, +5, and +3.3 volts are all okay, then your power supply is probably fine.

Unfortunately, a low voltage measured in this way may mean a bad PSU or that some other component (motherboard, etc.) has a short and is pulling the voltage down. Therefore, the main value of measuring voltages is to eliminate the PSU as a source of the problem (if it has normal voltages).
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You could either test the PSU voltages as above or use a known good PSU or assume it to be ok.

3. If the voltages are not ok [because of a faulty load] follow the chart instructions.

If your friend has little experience I'd advise her to get help from someone knowledgeable and experienced, or pay a professional to do the work.
Is the PC in or out of its warranty period?

[Benado1]

The computer is 2.5 years old, so I assume the warranty is over. I did tell her taking it in to a professional may be the best option, but I'll definitely run through your flowchart with her. (It's actually my fiancee's coworker whom I've never met, so depending on how things go, I may have a few more questions for you next week).

Cheers.

[ravin]

If your planing on takin the computer apart. Check to see if any of the capasitors look like the ones in this thread. I have is happening to the computer I'm on right now. When you first turn it on the hard drive, floppy, and cd-rom lights come on but no power to the CPU. Wait an turn it off and back on an its fine. Though I dont think they were made wrong like in the thread jest old. System is three years old. An I never would have noticed the problem if I had read about it in this thread.

http://www.pcguide.com/vb/showthread.php?t=25482