Well, I found out issue. It is that my CPU is hitting max temperatures. It is running like 75°C when being used. My room temperatures are like 35°C average so, 75°C is valid. So, as a protection windows freezes. I checked my BIOS. It is set to Auto overclocks.
I want to have some settings from BIOS that CPU doesn't go beyond 70°C. I can even compromise on performance for now.
Need system stability for now.
PS. I can't change Cooler due to budget.