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My computer is broken.
November 29, 2008 12:56 PM   Subscribe

I'm a novice computer-builder. My computer broke, and I think the motherboard is shot. Your thoughts? (detailed explanation)

One day I plugged my iPod shuffle into one of the front USB slots, and I got a "Device not recognized" error. I messed around with it for a while, but gave up soon after. A few hours later, the message started popping up incessantly, even though the iPod wasn't even connected. I still had a USB printer and mouse connected, though. Eventually the mouse stopped working, so I connected it with a USB --> PS/2 adapter. The next day, I found that the message had stopped occurring, and the USB slots were no longer working at all. After using my computer for a few minutes, the monitor randomly went blank. I opened up the case to see if the fans were still working. As I was staring at it, it shut off. However, the fans kept running, but they slowed down, almost to the point of stopping. Since the fans were still on, I shut off the power supply. Now, the front power switch does nothing. When I turn on the power supply, the fans start up, but then decrease in speed until they are "jittering."

I thought at first that maybe my power supply was bad, so I tested it. The tester showed that all the connections were good. The PS runs at full power when it's connected to the tester, but when I connect it to the mobo, it does not. I think the motherboard is bad - I don't see what else it could be.

Here is a video of me plugging in the PS to the tester, and then into the mobo (the video only shows the 20-pin connector, but I've tested all of them). You can see the fans slow down. You can skip to the end of the video to see the result (around 2:10):
http://www.youtube.com/watch?v=5GK8w2V5Fok

I've already ordered all new parts (cpu, mobo, video card, ram, PS) because my computer is out-dated and needs to be overhauled anyway, but I was wondering if anyone had any thoughts about what specifically could be causing this.

Another thing is, I noticed the front 120 mm fan was not moving because it was clogged up with hair/dust. I only had two case fans - 1 rear 120mm and 1 front 120mm (one sucks in air and one blows out). I've cleaned my computer a couple of times, but I must have missed that fan because it was somewhat hidden.

ALSO -- I am basically replacing everything except the drives and case. I've never tried this before, but if I installed all the new parts and tried to boot up off of my current windows installation, I'm guessing windows would throw a tantrum of sorts. Is this true? I've heard of people replacing a mobo and salvaging their current installation, but that seems rare.
posted by nel to Computers & Internet (10 answers total)
 
It could be a power problem. Have you replaced your video card already, or added new optical drives? Try changing the molex connectors that are going to your opticals.

That said, it's probably the motherboard. Check for shortages against the case.
posted by sonic meat machine at 1:09 PM on November 29, 2008


"ALSO -- I am basically replacing everything except the drives and case. I've never tried this before, but if I installed all the new parts and tried to boot up off of my current windows installation, I'm guessing windows would throw a tantrum of sorts. Is this true? I've heard of people replacing a mobo and salvaging their current installation, but that seems rare."

IIRC, Windows will break if you change the mobo.
posted by archagon at 1:28 PM on November 29, 2008


^I've done this three times, with both ME and XP, and while it is a pain in the arse it is possible. I wouldn't recomend it though.
posted by bizwank at 1:40 PM on November 29, 2008


You will have to reinstall Windows, however, if you have an actual Windows XP disk (of the same type previously installed on the drive -- i.e. Home, Professional, or Media Center), you can do a repair installation, which will basically just recopy all the system files without forcing you into a fresh installation of the OS. This usually works pretty well, so long as you have XP drivers for the motherboard.

As far as things wrong with the old motherboard, the most noticeable indicator of motherboard issues are bulging capacitors.
posted by The Great Big Mulp at 2:28 PM on November 29, 2008


Also note: there are a few different types of XP Professional whose keys are not interchangeable.
posted by The Great Big Mulp at 2:28 PM on November 29, 2008


Oh, one more thing I forgot: if your hard drive is a SATA drive, the Windows disk may say that something like "no drives have been found". XP Home and Pro do not have native SATA support, while Media Center does. There are two ways around this.

1) As the installation process is starting, across the bottom of the screen it will say something like "Press F6 to load Raid drivers from disk" or something like that. You can hit F6 at that point and load the SATA drivers from the disk that came with the motherboard.

2) This method is easier if the bios supports it. If you get the error message while trying to install windows, go into the motherboard's bios. There should be a SATA setting that should enable you to either emulate IDE or something like that. It generally has only two options, so if one isn't working, try the other one.
posted by The Great Big Mulp at 2:44 PM on November 29, 2008


Thanks for your answers!

Upon visual inspection, I couldn't see any bulging capacitors. A bad capacitor was a thought of mine. Can a capacitor be bad even if it isn't bulging/leaking? I'm no EE, but I know basic principles of capacitors, etc.

Also, if the front fan was kept from moving, wouldn't this create some access current, which could cause some other problem?
posted by nel at 3:57 PM on November 29, 2008


Mobo swap without reinstall. Haven't done this myself, but the theory looks solid.
posted by flabdablet at 6:44 PM on November 29, 2008


I'm guessing windows would throw a tantrum of sorts. Is this true? I've heard of people replacing a mobo and salvaging their current installation, but that seems rare.

Yes, you need to do an repair install. Its important to rebuild the HAL if you are moving from a single core to a dual core.
posted by damn dirty ape at 9:56 PM on November 29, 2008


I have actually short-circuited my computer (somehow) or destroyed my motherboard by plugging an iPod in. The PSU was a stock one, there was lots of dust, and the computer was 2-3 years old so maybe that's why. Always invest more money for a non-stock PSU because it's worth it in the end. Anyway, your problem looks like a mobo problem, because my fans were spinning but the computer didn't actually work as well. Also, you said you just shut off the power supply when the computer is on. It's not a very good idea and is better to turn off the computer first.

If you get new parts, if the mobo is the same, you can keep the currrent installlation. A different mobo means you need a new instllation.
posted by rintako at 12:04 AM on December 8, 2008


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