Computer Won't Power Down After Shutdown

[Drklighter]

Greetings...

Preliminary:
A short while ago I built my friend a new computer system. This system is VERY close to my own in hardware and software. I have been working with computers for more than 20 years, and I have a small hobby-business of building/working on PCs and related software. The problem I am having with his system started about the time that I built the system, and has lasted through various hardware/software changes.

The Problem
After using his computer for awhile, when he goes to Shut Down (to turn it off), it will sometimes shut the "system" off (HDDs/OS?) but will remain powered on. This happens randomly without any sort of pattern I have been able to discern so far. I have Googled the heck out this issue, but it doesn't seem to be a well-known phenomanon.

The Current System
ASUS M2N32-SLI Deluxe Wi-Fi MoBo
Athlon64 X2 6000+ CPU
Corsair XMS2 2GB PC6400 DDR2 (2x1GB) Dual Channel RAM Kit
2 x eVGA 8800GT 512MB Graphics cards in SLI (latest non-BETA Drivers)
Soundblaster X-Fi Xtreme Music PCI Card
LG GSA-H55N SATA DVD Super Multi Burner
LG GSA-4163B IDE DVD Super Multi Burner
3.5" Floppy Drive
WD 250GB SATA2 HDD (Primary, with WindowsXP Home SP2) *Dual Boot*
WD 250GB SATA2 HDD (Secondary, with WindowsXP Pro SP2)*Dual Boot*
PC Power&Cooling Silencer750 750W Quad-SLI ATX 2.0 PSU
Silverstone TJ-07 Tower Case with LOTS of air cooling
All latest drivers and DirectX
AVG Anti-Virus
Logitech G15 Gaming Keyboard (USB)
Logitech MX1000 Wireless Mouse (PS/2)
Wireless = DISABLED, Internet/Network via onboard GigaLAN

What I Have Tried
> Current Video Cards replacing OCZ 8800GTX 768MB
> Replaced second SATA DVD Burner with IDE Burner
> Current PSU replacing Enermax Liberty 620W PSU
> Reformatted and Reinstalled Windows on both drives
> Removed X-Fi, tried onboard sound and NO sound at all
> Disabled Firewire
> Reinstalled several drivers
> Disabled nVidia Driver Helper Service
> Changed LAN Ports
> Changed LAN Cables/Router/Connection
> Both HDDs are new & Replacements
> Shutting Down Hot & Cold (happens under both circumstances)
> Nothing in Error Logs
> Used Tweak Manager to enable "Power Down After Shutdown" Reg Entry
> Checked all Power Management settings in BIOS and Windows
> Have tried a number fo other "little things"

What I Have NOT Tried
> Using another Keyboard & Mouse (Trying that next)
> Replacing MoBo, RAM and/or CPU (Can't really dot his unless I know that's the problem)
> Replacing PSU (This is the second one we tried, I can't believe we'd have that bad of luck
> Reinstalling bare Windows again, then see if it happens with just the OS and no other software (I'm sure it happened on my last reinstall though).
> Adding Ethernet card (no available slot without pulling X-Fi)
> Updating BIOS (There's only one newer and it says it's only for CPU support)


I'm not sure what else I can do... I'm leaning towards this being a hardware issue, but I just can't tell him to start replacing key parts without at least an idea of what's wrong. Keep in mind, other than the video cards (I have a 8800 Ultra), SATA Burner (mine are both IDE), PSU (mine is a Silverstone 850w) and wireless mouse (I have a Logitech G5), we have virtually the same systems... I have the same XP Pro install on my main HDD that he has on his Secondary HDD (the one I am using to troubleshoot). Other than the AV and his use of iTunes we have nearly identical software as well... and I have NO issues.

He is a friend, but I am not about to start pulling my system apart to provide "test" parts for his MoBo, CPU and RAM... I need some more direction as to the problem. If anyone could offer some concrete advice/assistance I'd truly appreciate it.

Thanks!

 

[Drklighter]

UPDATE: Changing APM to S1, changing KB and Mouse to other PS/2 and disabling USB controller all still result in shutdown problem.

 

[Drklighter]

UPDATE: Tried new PSU - didn't fix it... going to assume it's the Mobo. Going to do a stripped down out-of-the-box test this weekend as a final test though.

 

[leetskeet]

my asus board completely crapped out last week. theres a conspiracy.

 

[Term-X]

Sorry if I didn't see it in your post but has your friend tried formatting? Honestly, my Windows XP installs would usually do that after 8 months or so.

 

[phongus]

did you try editing the registry in order for this to work? it should be working your computer should be shutting down all the programs if its stuck there -> task manager find out whats keeping it from shutting down after the first couple of attempts to manually shut it down.

last resort is reformat.

 

[Drklighter]

Update: After extensive testing, I have decided that the problem likely lies in a bad USB controller on the MoBo... it's been RMAed.