Wikipedia
CHKDSK
CHKDSK (short for "check disk") is a system tool in DOS, OS/2 and Windows. It verifies the file system integrity of a volume and fixes logical file system errors. It is similar to the fsck command in Unix.
On Windows NT operating systems, CHKDSK can also check the disk surface for bad sectors and mark them. (In MS-DOS 6.x and Windows 9x, this is a task done by Microsoft ScanDisk.) Windows Server version of CHKDSK is RAID-aware and can fully recover data in bad sectors of a disk in a RAID-1 or RAID-5 array if other disks in the set are intact.
CHKDSK can be run from DOS prompt, Windows Explorer, Windows Command Prompt or Recovery Console.