Question Heatsink making rattling noise

[Akronox]

A few days after building a computer the heatsink started making a rattling noise. I've opened up the machine and determined that the rattling noise was coming from the heatsink area. I determined this by stopping the exhaust fan, but the rattling noise was still being heard. While building the computer I had a problem with the Pure Rock 2 Slim from Be Quiet. One of the clips was almost impossible to clip on, and my dad and I made sure we were actually putting the clip in the right way. We got a bit scared because the motherboard was bending while trying to clip it in, so we just left the clip into the hole, and left it as 3 clips. The heatsink was still sturdy, but maybe something came loose. Can anyone help? If I'm missing something, let me know.

 

[NightHawkRMX]

If you stop the CPU fan does the noise go away? Make sure no cables are stuck in any fans.

 

[Akronox]

If you stop the CPU fan does the noise go away? Make sure no cables are stuck in any fans.

I've stopped the CPU fan and the noise went away. Maybe the heatsink is not tight enough and the fan is the one vibrating the heatsink, therefore causing that rattling noise? I may have just figured it out myself...

EDIT: I opened up the system and figured out the cooler wasn't the culprit, it's actually the PSU. It makes a sound like if an HDD were reading something but at least 3x louder.

 

[NightHawkRMX]

Well given the ugly cables and it's a prebuilt, it's probably a very low quality PSU. Might be a good idea to upgrade it both for longevity and noise.

 

[Akronox]

Well given the ugly cables and it's a prebuilt, it's probably a very low quality PSU. Might be a good idea to upgrade it both for longevity and noise.

It's a Corsair TX750W 80Plus bronze certified PSU