Chkdsk.exe is an utility used to check for errors in the disk media and in the file system. If you face problems ranging from blue screens to inability to open / save files / folders, you should run chkdsk.exe. Check Disk can run automatically, in the case of an abrupt shutdown or if it finds the file system to be 'dirty'.

The basic version can be accessed as follows : Open Computer > Rt-click Drive > Properties > Tools tab > Check Now. Here you have options to Automatically Fix File System Errors and Scan For And Attempt Recovery Of Bad Sectors. You may have to schedule the chkdsk at reboot, if the drive to be checked, is in use.

And then there is this "other" version of chkdsk which allows you several options, apart from just allowing you to set up regular disk checking using the Task Scheduler.

Open a Command Prompt Window, using the 'Run As Administrator' option, and then type chkdsk at the prompt.This will run Chkdsk in a Read-Only mode and display the status of the current drive. To get a report for, say, drive C , use "chkdsk c:".

/f
Fixes errors detected.

/r
Identifies Bad Sectors and attempts recovery of information.

/v
Displays list of every file in every directory, on FAT32. On NTFS, is displays the cleanup messages.

/c
Skips the checking of cycles within the folder structure.

/i
Performs a simpler check of index entries.

/x
Forces the volume to dismount. Also invalidates all open file handles. This should be avoided in Desktop Editions of Vista, because of possibility ofdata loss/corruption.

/l[:size]
It changes the size of the file that logs NTFS transactions. This option too, like the above one, is intended
for server administrators ONLY.

/p
It performs an exhaustive check of the current disk

/r
It repairs possible damage on the current disk