PC freezes without a reason

[MadMurl0c]

Hey,

some time ago I had Windows 10 installed on my system but because I got some Bluescreens after the Anniversary Update and decided to go back to Windows 7. The Problem was solved and everything worked fine... for some days/weeks. After a time my PC started freezing without a reason, no matter if I played WoW, Rainbow 6, GTA V or just watched youtube videos. My System is overlocked so I tried the default settings and this didn't solve the problem. The freezes doesn't appear everyday but sometimes they appear 4-5 times a day. I already googled for it but didnt found something that helps, I hope you guys can help me out

 

My System :

CPU : AMD FX8320 @4240Mhz - 1.3625V

GPU : AMD R9 290X @1080Mhz Core

RAM : G.Skill RipJaws 1333Mhz (8GB)

Mainboard : ASRock 970 Performance

SSD : Samsung SSD 850 Evo

PSU : be quiet Straight Power e7 700w

 

Already tried prime95 stress test for 4 hours without a failure.

Overheating can't be the problem too, while gaming my CPU is between 41°C and 54°C and my GPU is between 40°C and 67°C

[Funtron5000]

Try running Memtest

[MadMurl0c]

MemTest didn't report any Errors so I also checked my SSD for Errors, nothing.