Sometimes in computers that run Windows 7 the following problem appears: When you try to do a shutdown, the PC doesn't turn off completely, with all fans and LED’s remaining on (working) and the only way to power it off completely is to continuously press the Power button. In our case this problem appears on a customer's PC running Windows 7 OS with a Core 2 Quad Q8400 CPU (running at 2.66GHz) on a Asus P5K Deluxe motherboard.
The actions performed to resolve this problem, but without success, were the following: *
Notice*: All actions are performed without any external USB device(s) (e.g. USB Flash Disk, etc.) plugged in.
1. Replacement of Power Supply device.
2. Fresh Installation of Windows 7 OS (Professional Version) and latest Windows updates.
3. Installation of Microsoft HotFix (Fix297411) for similar problem: http://support.microsoft.com/kb/977307.
4. Hardware Clear (Reset) CMOS settings.
5. Modification (Enable > Disable) ACPI / APIC settings inside BIOS Setup.
6. Bios UPGRADE to the latest version (ver. 1005) – Motherboard: Asus P5K Deluxe / WiFi-AP.
After doing all these, without any success, the only solution that worked at last, was to modify the Power Settings for the on-board Firewire and Ethernet devices in Windows Device Management.
If you face a similar problem with you computer, then try this solution:
How to modify Power settings for hardware devices.
Step 1: Open Computer Device Management.
To Open Windows device management on Windows 7 Operating System:
1. Go to “Start” and then right-click on “Computer” and from the drop-down menu, choose “Manage”.
2. Choose “Yes” to “User Account Control (UAC)” warning message.
3. Click “Device Manager” at the left navigation pane.
Step 2: Modify Power Settings for Firewire and Ethernet devices.
Modify power settings on your Firewire (IEEE 1394) device(s).*
Notice*: Repeat the same operation for all IEEE 1394 Controllers.
1a. Look at the right pane and after expanding “IEEE 1394 Bus host Controllers”,
1b. Right click on your IEEE 1394 controller(s) (e.g. “VIA 1394 OHCI Compliant Host Controller”) and choose “Properties”.
2. At “VIA 1394 OHCI Compliant Host Controller” properties window choose “Power Management”.
3. At “Power Management” tab, UNCHECK the “Allow this device to wake the computer” option and press “OK”.
Now modify the power settings for your Ethernet (NIC) adapter(s).
Notice*: Repeat the same operation for all Network adapters
4a. Expand “Network Adapters”.
4b. Right click on your network adapter(s) (e.g. “Marvell Yukon PCI-E Gigabit Ethernet Controller”) and choose “Properties”.
5. At “Marvell Yukon PCI-E Gigabit Ethernet Controller” properties window choose “Power Management”.
6. At “Power Management” tab, UNCHECK the “Allow this device to wake the computer” option and press “OK”.
7. Restart and then try to Shutdown your computer.
In my case, using the above procedure, the computer was completely shutdown without any problems.