CHKDSK analyzes the physical structure of a disk to make sure that it is healthy and it can repair problems related to bad sectors, lost clusters, and directory errors. These types of problems can be caused in many different ways ie. System crashes or freezes, power glitches, incorrectly turning off a computer can also cause corruption in the system files etc.. Physically bumping or knocking a computer can cause the head that reads disks to hit the surface and damage sectors. Once some sort of error occurs it can end up creating more errors so a regularly scheduled disk check is part of good system maintenance. CHKDSK can also serve as an early warning that a hard drive is deteriorating, disks will gradually wear out and sectors may become bad. Go to the Start menu and click Computer. For Windows 8 and 10 users you can press the Windows Key + E. Right click on the drive you want to scan and select Properties. Then click on Tools tab Click on Check Now... under the Error-checking section. OK, here you will have a couple of options within the CHKDSK tool. It's recommended you leave the automatically fix file system errors checked, This option will attempt to repair any problems found. To perform a deeper scan, Check Scan for and attempt recovery of bad sectors. This option will take a bit longer. NOTE: Recommended checking both options..... saves you having to run another scan if something is wrong. When you have made your selection just hit the Start Button. If you are attempting to scan a Drive that is in use you will be faced with the image below, so just click on schedule disk check and the next time you reboot your computer it will run the CHKDSK scan. Hope you found this useful!