The core error is a failure of some code that is critical to Windows. If you've ever found a Blue Death Screen (BSoD), you've seen a core problem. Windows is actually some songs of programs that are made to work together. You can think of Windows as if it were your body, with many pieces that work together to create a whole, and like your body, some of Windows's components are more important than others.
The essence is the most important part of Windows. It includes critical applications for handling things like memory management and device driver for the video card. These plans are like the body of the heart and brain. If something in the kernel collapses, it will often cause all windows to crash.
Because there are plenty of applications in the kernel, there are many possibilities for bugs to appear. While Microsoft does extensive testing to get rid of bugs, their testing capabilities can not go through any combinations that billions of computers use with Windows when some bugs get through.
However, many hardware malfunctions are written by companies that create hardware, not Microsoft. Your graphics card, for example, probably uses a driver created by the video company. These companies often work with Microsoft to test their drivers, but by working together, adding additional layers is complicated.
Hardware failure can cause core failures. If the video card fails, it can send bad data to a graphics device driver, which then collapses, create a kernel error. If your hard drive fails, it may damage files used by Windows and cause the applications that use these files to crash.
Registry mistakes can cause kernel errors. The registry is a database of information that Windows uses to store application information. If the registry is corrupted, the applications that use it can cause kernel errors.
Registry corruption can occur from either software or hardware failures. Software corruption can be a bug in one of the programs that writes information into a registry. Or if you turn off your computer without completing the shutdown, the registry can not be fully written on the disk. Hardware corruption can happen when the hard drive fails, causing parts of registry files to be lost. It's a good idea to do some research on nuclear spikes and other registration problems.