When you run ChkDsk without taking a volume offline, the results are NOT accurate.

You can use the Vrfydsk.exe tool to check the integrity and consistency of a specified volume.

NOTE: See Windows Server 2003 Resource Kit Tools can be installed on Windows XP.

NOTE: Vrfydsk.exe cannot fix any errors it reports. To fix any errors, use ChkDsk.exe with the /F or /R switch.

When you type Vrfydsk /?, you see:

Checks a disk and displays a status report.

VRFYDSK \[volume\[path\]\] \[/V\] \[/I\] \[/C\]

  volume          Specifies the drive letter (followed by a colon),
                  mount point, or volume name.
  /V              On NTFS: Displays cleanup messages if any.
  /I              NTFS only: Performs a less vigorous check of index entries.
  /C              NTFS only: Skips checking of cycles within the folder
                  structure.

The /I or /C switch reduces the amount of time required to run Chkdsk by
skipping certain checks of the volume.
To check the C: drive:

1. Open a CMD.EXE window.

2. Type vrfydsk C: /V and press Enter.

NOTE: Vrfydsk.exe uses the Volume Shadow Copy service to create a temporary reduced shadow copy of the volume, which it checks.