One fine day you start your PC and get messages that say,?Book Disk failure?. The problem is that the hard disk is detected but the OS does not load. The system may get stuck in the second screen during the booting process or the OS might display an error message and refuse to load. Such situations can be trouble some as they leave you with very few troubleshooting options

One of the common problems in dual boot systems is of the boot loader getting corrupted. For example, you have a system running Windows XP and Linux using Lila as boot loader. If Lila gets corrupted, you can not boot into either OS.When this happens, you have to boot into the system using some other media, such as a boot floppy or the Windows Dafter booting go to the command prompt, type ?fdisk/mbr? and press [Enter]. Note that if you use Windows 2000 or XP, boot into the recovery console and give the command ?fixmbr? to clear the MBR. Unfortunately, after you restart, it will boot to Windows directly, without any option of booting into Linux. You will have to restore LiLo again from your Linux CD, or reinstall boot loaders such as XOSL from Windows.

If your problem persists, or if you never used a boot loader, than boot into the system from a boot floppy or the Windows CD.Windows 2000 and XP users should boot into the recovery console. Go to the command prompt and give the command fdisfk/mbr?and then give the command ?sys C?. This clears the MBR, and makes the bootable partition C, Windows 2000 and XP users should give the command ?fixmbr? and? fixboot? C: to do the same. Then restart the system to boot into the OS.

If you still have trouble, you might have a virus on your PC's boot sector .It is difficult to confirm an infection without a virus scan. Thesymptoms of an infections-applications slowing down or many unrecognized files appearing in the system-should give you a clue. For example Windows 98 and Me users might see a message during boot up that says,? No valid FAT on boot drive? this is caused due to a boot sector virus called stoned Monk. Even reinstalling Windows might give you an error message that says, ?Your computer already has an operating system installed?. Then best solution is to connect the hard disk to another system, and scan with an anti virus tool. You can also create a rescue disk for the anti virus tool and scan the system using it.

If nothing mentioned above seems to work. Then you have a serious problem at hand. Connect it to some other system and try to access the data if you can, then your boot record is damaged. Otherwise the service center beckons.