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Recently we experienced a power outage, and the PC was off. However, once the power came back, I switched on the PC and heard a strange noise - almost as if the hard disk or fans were struggling to work. I can't really describe the sound, but it's a laboured, loud sound almost like a jack-hammer. This has been persisting ever since the power outage, however the noise stops after around 10 minutes or so, and doesn't start again until the computer is turned off and on again.

At first I thought it had something to do with the HDD, but all my files are intact, chkdsk did not report any issues and performance is 100% unchanged, even in games (so the gfx card is fine, and so is the HDD most likely).

My PC setup basically has around 3 cooling fans, but I'm not sure if it's one of these either as the noise actually stops after 10 minutes or so, and if I leave the PC on for 4 hours (for example) the noise never starts again. It's there solely when turning on the PC.

I haven't got a UPS, and it's important to note that the computer was not on when the power went out - it was merely plugged in. I then promptly unplugged the PC once the power was out, and only plugged it in again when the power came back. Could it be the power supply? Unfortunately I can't open my tower as I would void the warranty.

Are there any tests which I could carry out without voiding the warranty?

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It seems that the hard drive is getting old (do backups, man), and it's unrelated to the power outage. – Jan Dvorak Jan 24 '13 at 8:29
The hard disk isn't old at all, I bought the PC 3 months ago :/ – Dot NET Jan 24 '13 at 8:30
@DotNET - Its entirely possible the HDD was bound to fail, HDDs can be defective, and only events like this are the trigger for the failure. If opening the case is no an option send it to the manufactor for a warranty claim. There is no way to figure out the reason for the noise without having physical access to the machine. – Ramhound Jan 24 '13 at 12:27

I guess there's not much to do without opening the case, but I think that there should be no problem with the HDDs. If a sound like the one you described came from the HD, it would be seriously damaged and it should not read anything. The other mechanical parts of a PC are CD/DVD readers, floppy readers or cooling fans. To exclude the CD reader, just put a CD in and try and read its content.

Most likely this is a fan problem. These are not vital to the computer: if a fan stops working and a component overheats, the computer will power down automatically to prevent damage to that component. The only fan that you can check Without opening the case is the PSU fan, if it has any. You could monitor the CPU and GPU temperatures to check if their fans are working correctly. If all of them are, then the problem might be with a case fan, but that is not a primary problem.

Of course if your computer is in warranty, you could ask for assistance. If a fan is not working correctly, they will replace it. If it breaks completely when the warranty is over, you will have to pay to replace it.

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DVD drive is working fine, as is the HDD I suspect. It's a gaming PC so I specifically ordered 3 cooling fans besides the integrated GFX card fan. Not sure if the PSU has a fan though. The strange thing is that the noise actually stops and is only present when booting and for a few minutes after that – Dot NET Jan 24 '13 at 8:32
I managed to fry both fan power pins on one of my motherboards when the CPU fan failed from dust, and I had to use an IDE power => fan power adapter. I don't recommend neglecting failing fans. – Jan Dvorak Jan 24 '13 at 8:32
Another possibility is that a cable fell from its position and is hit by a fan. This could eventually cause the fan engine to break. Since I read that your PC is 3 months old I would definitely request an inspection. – Pincopallino Jan 24 '13 at 8:58

Just open the case, unconnect the power to the harddisk, start the computer again. Then if you hear the noise, it's not the harddisk. If you don't hear it, it is the harddisk.

If it is the harddisk, buy another and make sure you make an exact copy (image) so you can switch them afterwards, or make a backup of your data files and user profile.

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I recommend reclaiming the old hard drive as well. – Jan Dvorak Jan 24 '13 at 8:40
The OP stated that opening the case would void the warranty. – Pincopallino Jan 24 '13 at 8:55
up vote -1 down vote accepted

Update: The cause of the problem was infact the power supply. Many months later it finally stopped working completely, and was changed through warranty. The noise then stopped after a new PSU was added.

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