The typical computer hard disk consists of gigabytes of data clusters that each have their own “reference” for an OS like Windows to access when the computer is turned on. The integrity of this “data library” needs to be maintained at all times, but that integrity is jeopardized when the computer is turned off suddenly while the HD (hard drive) is busy extracting data from its memory base and RAM. This can result in data corruption, hence the need for the chkdsk utility.
Running the chkdsk (check disk) tool is quite necessary to ensure no data damage or bad sectors have occured. A normal scan of the hard disk normally is prompted by Windows when you start up your computer; but if Windows does not detect any need to run a chkdsk scan at start up, it just means that nothing is wrong from the point of view of Windows. However if your hard drive is failing, or in the first stages of failing, you will notice the prompts for chkdsk getting more and more frequent whenever your computer gets shut down abruptly. When you notice this, it’s time to think about how to back up your data and get a new HD.