Power down; fans & USB stay on

My power down/power up procedure in Vista 32 goes as so:

1. Power down in Vista.   Computer appears to power down normally (monitor loses signal, drives stop spinning, etc) except fans and USB devices stay on.
2.  Holding in the power button doesn't shut the system down at this point.   I must turn off the switch on the power supply to shut down everything.
3.  Turn on the power supply switch.   Push the power button on the tower.   Fans & USB come on; computer does not.
4.  Hold in the power button.  Everything powers down.   Hit the power button again, and everything powers up like it should, and I go into Vista with no problems.

I'm using a P5N32-E SLI mb.  

Any ideas?
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Maybe your power button is set to sleep in power management options. I would nuke sleep and/or hibernation and see if anything changes.
Check the BIOS Power Management settings. It might be set to Hibernate or Sleep.

Does it turn OFF by itself after awhile if you leave it alone? It might be a "cooling down" thing.

>> 3.  Turn on the power supply switch.   Push the power button on the tower.   Fans & USB come on; computer does not.

Power Button is probably set to "resume last state on power loss" (or something like that).
That setting is usually in the BIOS Power Management section, also.
I really need to learn to type faster.   ; )
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can also be your power supply is causing it
telemudcatAuthor Commented:
I have 3 choices for "ACPI Suspend Type".  [S1 (POS)] [S3 (STR)] [S1 & S3]

Which should it be set at, and what does each mean?   It is currently set at S1&S3;  this is the BIOS default and I haven't touched this setting.  
You should set the default settings (optimal default), and then in Bios to browser the USB in either power option or USB legacy to turn it off options such as wake, allow usb to turn on ...., etc. I have seen usb options in bios on new mobo that you can setup settings above, and when it is set, the PSU will not turn off even you shutdown PC in normally way.
This is a defect with either your mobo or your power supply.  The fans and USB devices are receiving power from the standby rails and they shouldn't be.
I would try S3 only.
If that doesn't work, try Disabling the main Power Management setting.

The Sx meanings:
S0 - system ON
S1 - light Hibernate, fans keep running, ram still ON
S3 - heavy Hibernate, everything is OFF, but ram.
S4 - fully OFF or Hibernate.

Make sure the Vista Power Management is set the same as the BIOS. You can also disable one or the other, and use just the hardware (bios) or software (Vista), if you want to use Sleep/Hibernate on your system.

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Here is a pretty good article on setting it up:

Forced accept.

EE Admin
Thank you much.    : )
suggest googling dumppo and setting it right (vista does strange shit with operating levels thiss will set the acpi config in system32 coorectly)
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