How to diagnose a laptop that keeps freezing

Hi folks,

I have a Samsung RC-720 which I bought a few years ago which has recently started freezing. It's a real pain and happens maybe once a day.
I've had issues with the power in the machine before and believe it could well be related to the battery. In fact, it has frozen more than once upon connecting my charger to the machine. I have a replacement charger and switched to that, hoping to solve the problem - however, I still get these repeated freezes.

Firstly, would a new battery possibly solve the issue? Secondly, is there a way to actually diagnose and pinpoint exactly what is causing these issues, whether hardware or software? I tried using Event Viewer, and I see a constant stream of Event ID 41 - Kernel Power issues. However, all that tells me is that the system has rebooted without a clean shutdown - not what is actually causing the shutdown.

Any help would be much appreciated!

Thanks,
Andrew