Asus P5E-VM won't shut down

Got a new one here.. I have a new build E8400 CPU on an ASUS P5E G35 chipset mobo with Vista installed. When I select shut down from the start menu, windows promptly logs out and says shutting down. The screen goes black and everything seems ok. The problem is that the CPU fan, two case fans, and the PSU fan all remain running. The power led light at front of case is off as it should be. Upon pressing the power button, nothing happens. If I hold the power button for 4-5 seconds, then the fans and board will fully shut off. Then I can turn it back on by pressing power button, but not before holding it in long enuf to kill power. Strangely, i can instead just press the reset button instead while the fans are still spinning and the computer will boot up as if it thinks I pressed the power button. The power and reset wires arent crossed, they been tried both ways. The PSU has been swapped also, as i was suspiscous of it... any ideas

 

Check the BIOS. Some BIOS's have power settings that will produce the behavior you're describing. Also check with the Vista power settings and make sure that it's set to "Shut Down" and not go into hibernation or some other stand by mode or power saving mode. If neither of these help, try shutting down with all of your USB devices unplugged. Sometimes USB devices can cause a PC to not shut down all the way. If that isn't it, check with Asus and see if it's a known issue with the BIOS version you have, maybe a flash is needed to update it. Lastly, try a different power supply if you have an extra or if a friend has one you can borrow. Maybe the PSU isn't 'letting go' completely when shutting down.

 

Unfortunately none of these suggestions has worked.. One of the first things I done with this machine is flash BIOS to the new 506 version. I've swapped power supplies also without any success. (A high end one) Settings in Vista are for shut down.