GTX 770 Fps drops

[stambo]

Hello guys.One year ago i bought my new pc:

i5-4670k
EVGA GTX 770 SC ACX COOLER
8GB Corsair Vengeance 1600Mhz
Gigabyte Z87-HD3
Corsair RM750 PSU

So when i bought it I played CS:GO with 300 fps while i had maxed out everything(anti aliasing and everything) and now i am playing CS:GO with 150-200 fps with Very low settings.Sometimes it drops to 100 even.Can u guys tell me what is wrong/how can i check what is wrong with my PC.
Thanks alot.

 

[Coolboy951]

uninstall the drivers with DDU driver uninstaller

 

[stambo]

i have tried that, i also fully reinstalled windows, everything is clear in my computer

 

[Coolboy951]

check heat temps and everything

 

[stambo]

cpu tems while playing are 45-55 and gpu is around 45-52 while 25 degrees in my room.