Pc keeps shutting down randomly

ExtreamChaozZ

Distinguished
Dec 24, 2014
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My pc keeps shutting down randomly and I don't know why. it only just started this yesterday and I have had my pc built since the start of the year.
I did start to overclock my i7 4790K but when I did this I noticed that my pc started to shut down randomly so I started to decrease the overclock in case it wasn't stable. I eventually got annoyed at it and then reset all my settings in the bios as if I never touched the settings, I did this by using the built in function in my bios. All I then did was activate XMP mode for my ram which I did when I first entered the bios and it has been fine.
So how can I stop this as it keeps happening even if am just browsing the internet, no matter how the load is it just keeps happening.
These are my parts if you need to know:
mobo: gigabyte ga z79a sli
cpu: i7 4790k
gpu: gtx 660 sc
ram: corsair vengeance 16gb (2 x 8gb) drr3
psu: corsair HX 750w I
wifi: asus pci ac68