Incompatible components? Why does my system crash?

Hi guys, I just bought my self some new components to upgrade my PC.
The only components that I kept from my last PC is the power supply (700W), RAM memory and the old Hard Drive.
The new PC components are as follows:
MB: SABERTOOTH 990FX R2.0
Processor: AMD FX-8370 Eight-Core Processor
Memorry: Kingston DDR3 PartNumber KHX1600C9D3/4GX (8 GB of memory)
Graphics card: NVIDIA GeForce GTX 1060 6GB
A 500GB Samsung SSD that my OS is on, the Hard Drive I use it to store various stuff on it.

The problem is that my system crashes (no blue screen or nothing), it just crashes like you would hit the restart button. And it does so not when I play games on ultra settings (when the components are drawing a lot of power and they are heated) It does so when I am doing stuff like watching a youtube video or reading a news article or watching a movie. I am stressing this because it does not crash when I am gaming (tested it for 8 hours plus of continuous gaming and never crashed during gaming) it does this only when I do quasi normal things and the PC is not heated or anything and it does it at random sometimes one crash after an other some times it can go for hours without crashing. The most heated component when it crashes is the processor and is about 45 degrees Celsius, plus minus a couple of degrees.
I have all the drivers installed that comes with the MB and the Graphics Card driver I got of the official website (except the sound driver, it gives me an error only on Windows 7, at this moment I have windows 7 Ultimate X64 but the sound works just fine without the driver because I use headphones).
The same crashes under the same circumstances happen on Windows 8.1 X64.

Can't figure out what the problem might be. Can you please help me? Thank you.

No. I am saying that I kept the memory the list is about my new computer old parts and new ones.

Dudes, sorry it must be a language barrier. My old computer had the memory that I stated in the post and I am using it on my new computer, did not buy new memory because I deemed it not necessary. It's a set of two of 4GB each.

When I check the my reliability and problem history it just says:
Windows was not properly shut down.
And when I click on "view technical details" it says:
The previous system shutdown at 2:54:01 PM on ‎9/‎1/‎2016 was unexpected.

@ignatzatsonic
I Did not try and used any of the tests that you said, I will try them out right now.
And about the Device Manager, what am I looking for? How is it going to help?