Possibly it could be something stuck on the inside at a spot not easily seen and rubbing against the blades of the fan causing the noise. How old is your PSU? Maybe if it has been used for a long time and not maintained properly a malfunction can occur just from overuse. I'm not sure whether or not you should open the PSU casing and take a close look for anything out of place (I'm not sure if your PSU is even able to open or not, but if so make sure you take safety precautions). With a consistent blender sounding noise I would assume something is rubbing against the fan.

I can't see anything rubbing against it, and that's what I thought was wrong.

My PSU is only a year old.

Can you link me to your PSU. I know it may sound silly, but if I look at the model maybe I can make a better judgement about it. Also, are you certain it is the PSU? I would suggest opening your case (after you turn it off of course), pulling out the PSU (without disconnecting it), then turn on your computer and listen to hear if it is exactly your PSU making the sound. Sorry if it sounds like I'm telling you things you already knew but I'm not sure what you have tried so far.

Diablotek DA Series PSDA600 600W.

Hmm. There isn't lot of room to look inside. I would unscrew the casing and take a look inside. That is what I would do though. If you want to try it just make sure you are careful and stuff. I would hate knowing that I caused someone to break their PSU when just trying to fix it.

I might take it somewhere, I'm not the best with this kind of stuff, and I don't want to do anything stupid haha.

Thanks anyways dude.

Yeah no problem. Honestly with something like a random buzzing sound from the inside of the PSU I would assume it needs to be opened in order to figure out the problem. Good luck though and I hope it gets fixed.

Could be a power coil. Apparently if they are not properly secured (which often happens) the power coil will resonate and make a buzzing or whining noise. I don't really recognize that PSU brand and Google says it's crap, so it might behoove you to buy a new one from a reliable manufacturer like Antec, Corsair, Seasonic, or XFX. Shouldn't set you back that much. I have heard about some people taking apart their PSU to inject hot glue into a coil to stabilize it, but I really don't recommend that for you. Besides you might fry yourself on one of those big capacitors if you are not careful.

I was looking at this, seems a lot better, and yeah, it was included in a barebones package I purchased.

http://www.newegg.ca/Product/Product.aspx?Item=N82E16817139010

Depending on how the PSU is built, and positioned in the case try to look and see if the fan inside the psu is actually spinning. If it is, try sticking something in to stop the fan for a second (it won't damage it, just use something plastic) and see if the noise is still there. To me it sounds like a fan bearing is going bad, which is not a real big deal since its very easy (and cheap) to replace that fan.

Rule out the obvious and the easy to fix stuff first. Always check the fan when you hear a weird noise.

Bought a new PSU and SSD.

Merry Christmas to me.
Thanks for the help all.

You are very welcome. Enjoy the holidays.