CPU led on... for a while.

[BLima]

Hi, about 5 days ago my PC started failing to wake from sleep mode, at first I thought it was only a one time error, but it kept happening and it wouldn't start, even when shutdown and restarted.

The first time I couldn't get it started, the power button led kept blinking as it does in sleep mode and it wouldn't shut down by clicking it, I turned it off in the PSU and power it back on, same thing happened. I didn't worry that much and since it was late at night, I simply left it turned off on the PSU button. Next day I was able to make it start without any problem.
Then, when it went into sleep mode, it happened again, so I turned it off in the PSU, opened the case and tryed to start the PC, it didn't start and I noticed the motherboard CPU led was on.

I tryed a lot of things people suggested for similar problems, in other threads, but nothing worked except waiting for about 2 hours (no less) and start it like nothing's wrong...
Since I'm not willing to wait 2 hours to start my PC everytime this happens, I kept trying unplugging and re-plugging, re-installing the BIOS and lots of other things, nothing solved the problem.

Until now I was able to shut down and reboot without a problem (only happened when waking from sleep mode), but last time it happened after shutting it down from windows, went out for a while to stop thinking about the problem and now it started fine.

My PC:

Corsair CX600
Asus M5A97 EVO R2.0
AMD FX8320
2 Corsair Vengeance 4GB Ram
Asus Geforce GTX650 Ti

Everything was fine for about 5-6 months and this started happening suddenly, I hope someone can help with this problem and it just some stupid error. I can't understand why would it stop working, but start like nothing ever happened after 2 hours without power.

Thanks.

(Sorry if the text is confusing)

 

[Shaun o]

Next time you get the System to power on.
Go into the bios and the ACPI option.

Set it to enabled.
With S1 S3 And S4 as the modes.
Save settings exit bios.

Click on the link for explanation of what each S mode does and how windows os uses it.
If it is not enabled then it is why your computer does not wake up or shut down.
Also there is an option where in case of a power fail it can be told to stay powered off or restart.Not enabling the option in the bios is often the cause
http://en.wikipedia.org/wiki/Advanced_Configuration_and_Power_Interface

 

[BLima]

The BIOS has no clear ACPI options, some options mention "S modes", so I wouldn't know wich options to change. Anyways I didn't change any options recently and it was working fine until now, waking from sleep mode without a problem.

But as I sais: "Until now I was able to shut down and reboot without a problem (only happened when waking from sleep mode), but last time it happened after shutting it down from windows..."

So... now, it seems everytime the MB has a "power shutdown" either into sleep mode or an actual shutdown, I can't start the computer again. The only way it doesn't happen is with reboots, otherwise I need to turn off the PSU and wait for about 2 hours until the problem "magicaly" disapears without me doing anything.

 

[BLima]

Turns out the problem was the PSU, I would never guess this one! I tried a different one and it wakes from sleep mode, need to RMA the PSU. Hope that the next one last for a longer time.

Makes no sense to me why the PC would work after waiting 2 hours with the PSU turned off... but since it was the only thing I didn't try, before assuming that the CPU or the MB was the problem, I gave it a shot and my other PSU has only 4 pin CPU power connector so I didn't know that it could work and I didn't try it until I read some people said it was alright.

Thanks anyway, Shaun o