Pc randomly Reboots with out warning and with out showing bsod

[Big G]

Hi i have had this custom built pc for 12 months now and in the past 2 months my pc is rebooting and coming up with the (your pc has randomly shut down thing) i have cleaned all dust from my pc and have put a new cpu cooler in (noctua NH D15) thinking that it was the cpu overheating but it is still doing it please help i am not sure what is causing the problem
my specs:
OS: Windows 7 64bit
PSU: Corsair VS 650
Motherboard: Asus rog Maximus vi hero
GPU: Asus R9 270x
CPU: Intel i7 4770
Ram: Corsair Vengeance pro 16gb (2x8gb)
HDD: western digital caviar green 1tb
SSD: Crucial 240gb
cpu Cooler: Noctua NH D15
Case: Antec ninteen hundred

Anti Virus: Kaspersky
Malwarebytes

 

[Chris2005]

There are no dump files present.

Make sure Windows is configured to create dump files:
http://www.sevenforums.com/tutorials/174459-dump-files-configure-windows-create-bsod.html

All that should be necessary is to create a small memory dump.

 

[Big G]

going through my settings and the link you have i already have windows creating Kernel dump files

 

[Golden]

Check that the Noctua is correctly seated:
http://www.sevenforums.com/tutorials/220743-cpu-stress-test-using-intelburntest.html