A kernel bug is a bug in code critical to Windows. If you've ever encountered a Blue Screen of Death (BSoD), you've seen a kernel bug. Windows actually consists of several levels of programs that are supposed to work together. You can think of Windows as being your body. Many parts work together to form a whole, and like your body, some parts of Windows are more important than others.
The kernel is the most important part of Windows. It contains important programs for memory management and device drivers for the graphics card. These programs are like the heart and brain of a body. When something crashes in the kernel, Windows often crashes.
Since there are many programs in the kernel, there are many ways that errors can occur. Although Microsoft does extensive testing to troubleshoot problems, the testing features cannot go through all the combinations that billions of Windows computers use when some errors occur.
However, many of the kernel bugs are due to device drivers written by companies that make hardware, not Microsoft. For example, your graphics card probably uses a driver created by the video company. These companies often work with Microsoft to test their drivers. However, corporate collaboration increases complexity.
A hardware failure can cause a kernel failure. If your graphics card fails, it can send faulty data to the graphics device driver, which will crash and cause a kernel error. If your hard drive fails, it can damage the files used by Windows and crash the programs that use those files.
Registration errors can cause kernel errors. The registry is a database of information that Windows uses to store information about programs. If the registry gets corrupted, the programs that use it can cause kernel errors.
Damage to the registry can be caused by software or hardware errors. Software corruption can be caused by a bug in one of the programs that writes information to the registry. If you turn off your computer without shutting it down completely, the registry files may not be written completely to the hard drive. Hardware damage can occur if the hard drive fails and parts of the registry files are lost. It is a good idea to investigate kernel errors and other registry problems.