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You need to run chkdsk......

How to run Chkdsk

Notes

Chkdsk requires exclusive access to a volume when it runs. Therefore, if one or more of the files are open on the disk that you want to check, Chkdsk displays a prompt asking if you want schedule the disk check for the next time that you restart your computer.
Chkdsk might take a long time to run, depending on the number of files and folders, the size of the volume, disk performance, and available system resources, such as processor and memory.
Chkdsk might not accurately report information in read-only mode.

How to run Chkdsk at the command prompt

Click Start, and then click Run.
In Open, type cmd, and then press ENTER.
Use one of the following procedures:
To run Chkdsk in read-only mode, at the command prompt, type chkdsk, and then press ENTER.
To repair errors without scanning the volume for bad sectors, at the command prompt, type chkdsk volume:/f, and then press ENTER.

Note If one or more of the files on the hard disk are open, you will receive the following message:
Chkdsk cannot run because the volume is in use by another process. Would you like to schedule this volume to be checked the next time the system restarts? (Y/N)
Type Y, and then press ENTER to schedule the disk check, and then restart your computer to start the disk check.
To repair errors, locate bad sectors, and recover readable information, at the command prompt, type chkdsk volume:/r, and then press ENTER.

Note If one or more of the files on the hard disk are open, you will receive the following message:
Chkdsk cannot run because the volume is in use by another process. Would you like to schedule this volume to be checked the next time the system restarts? (Y/N)
Type Y, and then press ENTER to schedule the disk check, and then restart your computer to start the disk check.

How to run Chkdsk from My Computer or from Windows Explorer

Double-click My Computer, and then right-click the hard disk that you want to check.
Click Properties, and then click Tools.
Under Error-checking, click Check Now. A dialog box that shows the Check disk options is displayed,
Use one of the following procedures:
To run Chkdsk in read-only mode, click Start.
To repair errors without scanning the volume for bad sectors, select the Automatically fix file system errors check box, and then click Start.
To repair errors, locate bad sectors, and recover readable information, select the Scan for and attempt recovery of bad sectors check box, and then click Start.
Note If one or more of the files on the hard disk are open, you will receive the following message:
The disk check could not be performed because the disk check utility needs exclusive access to some Windows files on the disk. These files can be accessed by restarting Windows. Do you want to schedule the disk check to occur the next time you restart the computer?
Click Yes to schedule the disk check, and then restart your computer to start the disk check.

The following table lists the exit codes that Chkdsk reports after it has finished:
Exit code Description
0 No errors were found.
1 Errors were found and fixed.
2 Disk cleanup, such as garbage collection, was performed, or cleanup was not performed because /f was not specified.
3 Could not check the disk, errors could not be fixed, or errors were not fixed because /f was not specified.