I have had my computer build for about a year now and have never experienced this problem. Just recently, about a month or so ago, my computer would make an awful clicking noise. It is as if a fan is hitting something.
I've narrowed it down to the PSU and i have made sure there are no wires close to the openings. An yet it still makes that god awful nose.

I've blown (carefully) air and vacuumed it several times, both of which only stall the noise for about 3-5 minutes. Then it will start back up again at random times.

Anyone know what i could do ?

It is a Thermaltake Toughpower 650W psu. I'm not sure if it is covered under warranty anymore. I bought it off of NewEgg.

I'll try and get a video/sound recording of it with my camera and post it on here.