Yesterday I run the defragmentation utility on a computer which was moving very slow. Today I rebooted the machine and… the Windows XP Professional does not start anymore. The bugcheck (BSOD) UNMOUNTABLE_BOOT_VOLUME is what I get all the time.
I inserted the Windows XP installation CD and booted from the CD. Then I choose R (recovery).
At the DOS prompt I run
C:\> chkdsk C:
Now everything works fine.
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