Question Unsolvable PC lag and Stuttering, Please Help?

[ankit_sangeet]

I am from India, and i have a fairly average pc buildSpecs:-
CPU - i5 7400
GPU - MSI GTX 1060 3GB OC edition
Ram - Gskill Ripjaws 2400mhz 2 x 8GB sticks
Motherboard - Gigabyte B250m
PSU - Cooler master 500 watt lite
Storage - 480gb SSD. 1TB 7200 rpm HHD

My issue is, every component is working fine in my knowledge, everything from temperatures to thermal paste to Cpu cores are working fine, but still i find frame drops in my day to day functioning, like the videos are laggy, the green progress bars are stuttering and even i am facing way more less FPS than i used to get. Even the loading circle in the chrome browser tab is stuttering.
Also i have a weird constant static noise in my USB Speakers

https://www.dropbox.com/s/jh4mia1ra4k6f6b/Capture.JPG?dl=0 this is the stress test of CPU
https://www.dropbox.com/s/rskzef2ccstxwdl/Chrome.mp4?dl=0
https://www.dropbox.com/s/6nyqw3odzaly1zh/WhatsApp Video 2019-02-18 at 12.47.08 PM (1).mp4?dl=0

These are clips of minor stuttering i face.
Tried so far:-Reinstalling Windows,Updating each and every driver,Turning and even uninstalling Antivirus,Fiddling with registries, Nvidia control pannel,Please Help.
-Your Friend in need.

 

[Achaios]

CPU cooler is not properly seated thus causing the CPU to overheat. When CPU overheats the lag fest starts as it throttles down. Reseat CPU cooler and re-apply TIM. Tighten screws properly.

 

[ankit_sangeet]

CPU cooler is not properly seated thus causing the CPU to overheat. When CPU overheats the lag fest starts as it throttles down. Reseat CPU cooler and re-apply TIM. Tighten screws properly.

https://www.dropbox.com/s/rskzef2ccstxwdl/Chrome.mp4?dl=0
https://www.dropbox.com/s/6nyqw3odzaly1zh/WhatsApp Video 2019-02-18 at 12.47.08 PM (1).mp4?dl=0
There are no any signs of high tempratures in CPU. please watch these videos.

 

[Achaios]

There are no signs of high temps because YOUR CPU THROTTLES DOWN.

 

[ankit_sangeet]

There are no signs of high temps because YOUR CPU THROTTLES DOWN.

What should i do? 🙁 i feel helpless.