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So, I am pretty sure this will be a unique problem

One of my fellow employees took a cable with a RJ-45 jack on one end, and a USB on the other and thought it would be neat to plug the cable into the wall ethernet jack and the other end into the USB jack on his computer to see what happens. Trouble is the ethernet jack he plugged into was PoE and supplied 45 volts into the 5 volt USB controller and it immediately shut his computer down.

Now, the computer will boot up and make is past the POST without any problems, but when it gets to loading up Windows OS it will reboot about half way through/near the end of it loading. I have detached the USB controller from the motherboard so I could eliminate that possibility it was failing when loading the drivers, I memtested the RAM, the hard drive seems to be fine, and I can easily install Ubuntu without a hitch. But I can't get Windows to work

Any suggestions? My last thought is there is some controller or hardware failure on the motherboard that causes a reboot when Windows loads up a driver as opposed to Ubuntu not having the driver.

Many thanks,

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Try booting the system in safe mode, possibly with boot logging turned on. This should let you know what the system is doing when it restarts. Lesson to learn, kids! Computer hardware is never ok to "see what happens", unless you like magic smoke – Darth Android Aug 2 '12 at 21:37
Heh, sadly I can't run "Safe Mode" with Windows since I went ahead and installed Ubuntu on the drive to see if it would work. Guess I should have thought of that... – Stephen R Aug 2 '12 at 21:38
You might look at the output of dmesg to see if there are any issues that Ubuntu detects, but ignores when it boots up. I imagine something simply fried, and Windows doesn't know how to deal with it properly. – Darth Android Aug 2 '12 at 21:39
Sorry, but after a shock like that, it's pretty unlikely it'll ever work properly again. They put high voltage into sensitive electronics "to see" and expect it to work without a problem! – Deanna Aug 2 '12 at 23:27

That's true. Motherboard is damaged. USB ports are realized on the USB controller that can be external (plugged in to the slot) or on-chip, i.e. integrated into the south bridge of the chipset (replaced by the Platform Controller Hub (PCH) architecture introduced with the Intel 5 Series chipset in 2008). PCH is also responsible for the rest of the integrated controllers like audio, FireWire and network controllers. Any of them could be damaged as well. Also, electrical breakdown could also reach PCH chip itself.

The easiest way to detect the faulty controller is to touch it with a finger to detect if it is overheated. After that you can just disable them in BIOS. If it is PCH that is partially damaged, then some of its functions may not work normally. Why Windows is not working but Ubuntu does? They have different way of detecting devices and injecting required drivers during the installation.

Additionally, I advise you to start Windows PE from USB or CD/DVD drive that doesn't require installation - you'll get pure environment where you can test your USB. I advise to use Ieshua's Live DVD/USB ( or something like

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