I have Compaq computer using Windows XP professional. I couldn't boot it. I got error message "UNMOUNTABLE_BOOT_VOLUME". I rebooted computer with XP CD-ROM, clicked repair and ran chkdsk /r. After about 30 minutes, 25% of checking hard drive, it stopped with the error that the volume seems to contain one or more unrecoverable errors. I tried also the command fixboot and after replacement of boot sector, computer still gives blue screen with the same error UNMOUNTABLE_BOOT_VOLUME.
Any advice on how to fix the problem?