PC could not start... pls advise...

[onemilimeter]

The specs of my dekstop computer are as shown at my signature except the PSU used is a Seasonic X-650 (two months old).

At the moment my desktop computer can not start. This is the 2nd time. The first time it refused to start was about 1~2 week ago.

Once the power button is pressed, some leds on the motherboard are lit. See the figure below. The DDR Phase LEDs are in Yellow and Green. The Clear CMOS button at the rear panel is also lit. How can I restart my computer?

What will happen if I press the Clear CMOS button?

Thanks.

[Dark Mantis]

Hi onemilimeter long time no see,

Were these LEDs not on before the problem?

Try clearing the CMOS completely by following the directions.

Remove the power cable from the mains supply and then press the power switch on the case for a few seconds just to drain any residual energy in the PSU capacitors.

Once done remove the motherboard battery for at least ten minutes before replacing it.
 
Next plug back into the mains supply and boot.
 
You will now need to enter the BIOS by pressing DEL and load Opimised BIOS Defaults.

Make any other changes to the BIOS settings to suit your self and then press F10 to save and exit.

[onemilimeter]

Hi...

Thanks. I can't remember if the LEDs were on or not before the problem. I will follow your suggestion to reset the BIOS.

According to the manual:
"Clearing CMOS Button: Press the clearing CMOS switch to clear CMOS values"
Does it reset the CMOS to its default values or delete the BIOS kept insides the CMOS?

Cheers.

Hi onemilimeter long time no see,

Were these LEDs not on before the problem?

Try clearing the CMOS completely by following the directions.

Remove the power cable from the mains supply and then press the power switch on the case for a few seconds just to drain any residual energy in the PSU capacitors.

Once done remove the motherboard battery for at least ten minutes before replacing it.
 
Next plug back into the mains supply and boot.
 
You will now need to enter the BIOS by pressing DEL and load Opimised BIOS Defaults.

Make any other changes to the BIOS settings to suit your self and then press F10 to save and exit.

[Dark Mantis]

It will clear all the settings from the BIOS and leave you with the BIOS version that you are using now but with no settings, that is why you have to load the Optimised BIOS Defaults afterwards.

The LEDs were probably on before as you were using 1600Mhz memory and so it is slightly overclocked.

[onemilimeter]

It will clear all the settings from the BIOS and leave you with the BIOS version that you are using now but with no settings, that is why you have to load the Optimised BIOS Defaults afterwards.

The LEDs were probably on before as you were using 1600Mhz memory and so it is slightly overclocked.

I tried both, i.e. pressing the "Clear CMOS" button and removing the battery, but the computer still refused to start.

I unplugged the 24-pin M/B connector from the M/B and plugged it onto the M/B again. Then, the computer could be started. If my memory serves me well, when my computer refused to start 1~2 week ago, I did the same thing before it could start again. Weird... why did I need to unplug and plug the 24-bit M/B connector?

Thanks.

[Dark Mantis]

Hi
I suspect it would have done the same if you had done a hard reset by removing the power form the PSU and then discharging it. As to why it should actually make a difference though is another matter. I would run some diagnostics on it though and just check that everything is working as it should.

[onemilimeter]

Hi
I suspect it would have done the same if you had done a hard reset by removing the power form the PSU and then discharging it. As to why it should actually make a difference though is another matter. I would run some diagnostics on it though and just check that everything is working as it should.

I did switch off the suppy to the PSU and then press the casing power button to discharge the PSU but it still refused to start. Only when I unplugged and plugged again the 24-pin M/B connector then it started. The X-650's output connection is fully modular. Could it be anything to do with this "full modular" connection? I did not have such problem when I used OCZ600SXS in the first six months. But X-650 is a decent PSU... really don't where is the problem...

[Dark Mantis]

I wouldn't have thought that the power supply beng modular would have anything to do with it. I just can't see what difference it would make in removing the motherboard cable as opposed to unplugging from the mains and dissipating the residual energy.