All games are lagging and I don't know why

[Velozer]

Hey, guys, this is really frustrating I have an MSI GTX 970 and I was trying to overclock and it was fine it worked but I wanted to clean reinstall Windows 10 and I found that my pc feel kinda slow and stuffs like that I downloaded the Nvidia drivers and everything got everything set for gaming then I tried running Fortnite I started lagging and stuttering I was getting about 50-60 fps on medium settings which I used to get 150-200 fps before so I thought it was my SSD tried installing on my other SSD and even tried to reinstall windows 10 without other HDD or SSD plugged but no hope I still can't play any games I even tried running cs go but when I move I get around 10-15 fps before I used to get 200 fps on cs go I don't know what's going on even if I knew what the problem was I could search on google and fix it but I don't even know what's the problem right now please help me guys I wasted 2-3 days already on trying to fix. Thank You

 

[RARRAF]

And here's my pc specs:
Tablet/Laptop/Desktop/
CPU:
Motherboard:
RAM:
GPU:
HDD:
PSU make and age:
OS:
HWINFO from here https://www.hwinfo.com/download.php

 

[Velozer]

And here's my pc specs:
Tablet/Laptop/Desktop/
CPU:
Motherboard:
RAM:
GPU:
HDD:
PSU make and age:
OS:
HWINFO from here https://www.hwinfo.com/download.php

Desktop
CPU: Intel Core i7-6700
Motherboard: MSI Z170A GAMING M7 (MS-7976)
RAM: CORSAIR CMK16GX4M2A2400C14 8GB X 2
GPU: MSI GTX 970 Gaming (MS-V316)
HDD: ST1000DM003-1SB10C [1000 GB]
SSD:SAMSUNG SSD 850 EVO 250GB [250 GB] and GeIL ZENITH R3 240GB [240 GB]
PSU make and age: 600W and My pc is about 1 and a half years old
OS: Windows 10

Everything used to be so smooth but suddenly this happened after reinstalling windows 10

 

[Velozer]

i fixed the problem there was a thing on my motherboard it was written off and on for slow and i turned it back to off and now everything is going smooth