I ran a Socket478 ECS mobo, P4 proc, IDE drives, AGP8X video, XP SP2 for ~4 years. After about 1 year of expected behavior the system started behaving oddly. After going through the normal XP shutdown routine the screen goes blank and shuts off. However, the HDD does not stop but justs spins down to a lower speed and the HDD head starts ratcheting back and forth, at least that is what it sounds like it is doing. The HDD light flickers constantly at about a 10Hz rate. Also, the CPU and system fans do not stop, but just slow down. The only way the system will stop completely is if I turn the PSU off completely using the main PSU switch. Once the main PSU switch is flipped on again, the HDD light, HDD, and internal + CPU fans all turn on again, like they were previously. When the front panel power button is pressed the PC boots normally.
I checked the BIOS and disabled all the "Wake on ..." stuff I could find. This had no effect. I ran a bunch of virus scans, adware, spyware, etc, and found nothing.
I put up with this for about 3 years until the ECS mobo failed to see IDE0 (boot drive) a few times. I figured the mobo was about dead so I bought a new Biostar P4M80-M4 mobo and installed it a few days ago with all my old hardware. The system came up fine but still has the power-down problem. I ensured the new BIOS has all the "Wake on ..." stuff disabled. I also removed the video cable, LAN cable, etc, when the system is supposed to be powered down. This did not help.
Can someone tell me where to find the ghost in my machine?
Thanks in advance.