CS GO low FPS on my ACER E1-570G

[dexteran]

I have a pretty low end laptop.
CPU: Intel Core i3-3217U @ 1.80GHz
RAM: 4096MB
GPU: Nvidia GeForce GT 740M

The thing is, the game used to run on 60-70 fps until some 2-3 days back, but suddenly it has dropped to 20-ish. I have played around 350 hours with the previous settings and was pretty okay with it.
So what could be the problem here? I'd be glad if you can help me solve this problem here.

 

[Reynod]

You may have a virus or some malware running in the background which is using up resources.