Unusual ticking noise from fan

I purchased a new iMac for Christmas.

I have used it almost daily since then.

All of a sudden I have been receiving a sometimes quiet, but sometimes loud ticking noise coming from the behind/underside of the computer. Nonetheless the noise is prominent.

I have read a few articles on the web, some claiming it is a noise that suggests HDD failure, other suggesting that it could be a loose wire being slightly hit by the CPU fan as it rotates.

I downloaded smcFanControl and played around with the speed of the fans and it made no difference. I then called Apple Support and they took me through a few steps to reset the power supply, or something. It involved unplugged, starting up again whilst pressing cmd, alt, p, and r and a few other steps.

I am just wondering if anyone has encountered this position before and/or if anyone has a solution.

I am running OS X Lion version 10.7.3

Many thanks.

(PS: I will be able to upload a video of the noise, if need be.)

Since there are three fans in an iMac (not one, three...) a ticking noise could be coming from any one of them. Instead of trying to determine what's causing the ticking sound, make an appointment with your local Apple store genius bar and take it on in for them to look over. Getting inside an iMac is difficult and best left to the professional technicians at Apple.

Just sucks there isn't an Apple Store in my town, haha.

Yeah I understand there's three, I was simply going by what I've read on the Internet.

Thanks for the suggestion though!