UPDATE: I definitely think it has something to do with temperatures, because when the ambient temperatures go down after a slight drizzle, it stops happening.
However, I have set the PC to shutdown when the CPU hits 70 celsius. When the CPU hits 70 degrees, the PC turns off automatically. It doesn't freeze, it doesn't hang, it just powers off.
Once again, the PC turns off when the CPU hits 70C. It doesn't freeze and stop responding.
This freezing problem is unique and definitely has something to do with the ethernet, because it started happening only after I switched to ethernet, and doesn't happen when the internet is turned off.
It also doesn't happen when ambient temperatures are low.
I'm completely at my wits end trying to diagnose this issue. Google isn't much help either...