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Windows 7 64 bit. Was running a normal app (compiler IDE). System shutdown as if there was a power loss, but there was not... Started back up in Windows safe mode. Started up fine, but approx 2 minutes later, hard shutdown again. Waited approx 2 minutes. Started back up, went into BIOS. CPU temp at 121 degrees F (49.5 C), MB at 119 degrees F. All 3 fans running at approx 1200 RPM. System shutdown while in BIOS after being on approx 2 minutes.

Decided to open case. I see that my MB has a power button, which glows red (LED backlight, momentary on style), and a reset button. Both show power. Nothing appears wrong. Hit power button again, but now nothing happens. Tried power button on MB, but nothing. I shut off power in the back of the power supply. LED buttons no longer lit. Turned Power Supply switch back on, buttons light up again. Cannot turn on computer, either from MB button or from power button on front of case.

No new hardware added. System current with patches. Run MS Security Essentials. Fans rotate freely. Although there is some dust inside chassis, it is not excessive. System has never been overclocked.

System has a Core i7-920, with ASUS MB.
Power Supply is CoolMax CUG-950B. I note that there is a SLIGHT melted plastic smell coming from the power supply. System is approx 4 years old, and until just now, no other HW problems.

Any help appreciated.


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up vote 2 down vote accepted

Based on what you are describing, it sounds like your power supply is cooked (hence the smell). Probably a popped voltage regulator.

This is common, try a new power supply. :)

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The smell is not an intense smell, so I am little hesitant. There is a smell, but it is not strong. It is slightly acrid, a little like burnt plastic. Would this still be symptomatic? Any other possibility? Also, is it possible that the PowerSupply is only partly bad? i.e. I am still getting some power, because the power switch on the MB still lights up. – user1009073 Apr 8 '12 at 20:28
techie007 is correct. What you have described sounds very much like a failed power supply; especially the smell and the fact it would only operate for a few minutes at a time (because it was over heating then cutting out). A new power supply is relatively inexpensive compared to the rest of the computer. – CharlieRB Apr 9 '12 at 16:44
Replaced Power Supply. System is fine now. Thanks! – user1009073 Apr 16 '12 at 19:20

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