I own a Dell E6420 laptop, that runs Windows 10 Pro.
My laptop has this one issue. Randomly, out of the blue, it just freezes up. My touchpad becomes unresponsive. The DVD Drive switch would not respond. The fan would suddenly run at it's maximum RPM.
Removing the power cord would reflect in a small change in system brightness, in accordance with my power settings.
My laptop has a hardware switch to turn on/off the WiFi Radio, which is reflected my a small Wi-Fi light near my power switch. When the freeze occurs, toggling the switch doesn't turn off the light.
The system would not unfreeze at any point. The only measure would be to force power down by holding down the power button.
I've tried to keep track of the kind of circumstances under which this occurs. Some of the variables I considered were temperature, CPU Load, ambient humidity, presence of AC power (I usually run my laptop with the power cord attached), total running time. There was nothing common that I could find. It was all random. I always noted down the programs that were running whenever my laptop would freeze. Again, completely random. The frequency of these freezes are random too. Sometimes, my laptop would go an entire month without freezing once. Sometimes, it would freeze twice in a day.
The issue has been persisting even before I upgraded to Windows 10 from Windows 7.
The older Windows 7 was installed on a brand new 500 GB, 7200 RPM SATA Hard disk.
What can I do to overcome this?
Edit 1 : I use Avast Antivirus that always runs on the background and I perform weekly full system scans using Avast Antivirus and Norton Power Eraser. I've never encountered malware problems so far, so I think we can rule that out.