Very Strange Issue with Newish PC build

About a month ago, I upgraded nearly everything in my PC (GPU, storage, CPU cooler, PSU, motherboard).  I've been happy with the performance, but I have a recurring issue that I'd like to resolve.

Every once in a while, my PC will stop working and a buzzing noise comes from my headphones. The only thing that I can do is hit the reset switch or turn off the power supply.  This doesn't happen very often (only happen 3 times so far), but I'd like to be sure it doesn't happen again.

If any of you guys have any insight to my issue, I'd love to hear.

What is your power supply?

Describe "stop working".  BSOD?  Total freeze? Black screen?  Specs will help as well.

I'll just go ahead and post the full specs.

CPU: Intel Core i5-2500K @ 3.3 GHz

Memory: G-Skill Ripjaws 8GB

GPU: MSI Twin Frozr GTX 760

Storage: Samsung 840 EVO 120 GB and Seagate Barracuda 1TB

Motherboard: ASRock z75 Pro3

PSU: Corsair CS550M

Total freeze, and I've replied with specs above.