Hi folks.

Advice appreciated on a potentially partly self inflicted problem. Last Thursday my PC turned itself off completely without any warning whatsoever, twice in one day. Dismayed at this, I opened up the case and tried to remove all the dust I could from the Motherboard fan and the PSU, very carefully, with the aid of a vacuum cleaner which I did not let actually touch the components (I just held it in the air above). I also found a screw lying loose in the case and removed it.

However, it turned out to almost certainly be the case that the PC turning itself off was due to a problem with the general electricity supply in my area because my friend reported that PCs at his workplace half a mile from there were also turning off.

So all was well.. I thought, and my PC has indeed not turned itself off since. However, since the cleaning exercise, my PC occasionally makes this clicking noise, which I can only describe as the same noise that happens when you turn it off. Sometimes it makes it several times in a row.

A couple of times when this has happened, more worryingly, the PC has momentarily frozen. Sometimes it recovers quickly, other times, it takes about a minute before my PC returns to usability, and even then things are going slow. It seemed to fail particularly when reading/writing from the hard drive with my documents on it- once when saving a word document, once when playing an mp3.

The conventional wisdom would be that one of my hard drives (I have four.. figuring out which one is going to be fun if this is indeed the case) is failing. Is the clicking noise made when this happens the same noise given by a PC as it turns off?

However, given that it started happening the same day I did all those attempts at dust removal, during which I did not touch the hard drives at all, it does make me wonder if perhaps the problem is with the PSU instead? Or is it just co-incidental..