Cause

• If a computer fails while attempting to read the hard drive for a valid operating system to load, it will display an unmountable boot volume error message. This can be caused by operating system corruption, file structure integrity errors or a physically failing hard drive.
  
  

Repair

• In some cases, the unmountable boot volume error can be corrected by running chkdsk. This can be done by booting the Dell with the Windows disc or the Dell reinstallation disc in the drive, and pressing the appropriate key when prompted to boot to the CD. Once the computer boots, press the "R" key to access the recovery console and type "chkdsk /r" without the quotes. This will find and repair integrity problems. Once finished, type "fixboot c:" and agree to write a new boot sector.
  
  

Warning

• If chkdsk fails to correct the error, then a serious failure may have occurred and the drive will have to be replaced. Even if chkdsk corrects the problem, the error might be an early sign of a failing drive, and data should be backed up immediately