Invalid partition table
Error loading operating system
Missing operating system
Getting a message like this can be pretty scary and may cause you to overreact and try to reformat your hard disc and reinstall the operating system - thereby losing any data not previously backed-up.The cause of the behaviour noted above is generally a corrupt master boot record (MBR). Every hard disk must have a consistent "starting point" where key information is stored about the disk, such as how many partitions it has, what sort of partitions they are, etc. There also needs to be somewhere that the BIOS can load the initial boot program that starts the process of loading the operating system. The place where this information is stored is the MBR and it is always located at cylinder 0, head 0, and sector 1, the first sector on the hard disk. If
the MBR becomes corrupt then the boot process will fail as described above.
Typical causes of corruption in the MBR include it being infected by malicious code (viruses), becoming corrupted by disk errors, or being overwritten by other boot loaders when experimenting with multiple operating systems on a host e.g. GRUB or LILO used by Linux.
Generally corrupt MBRs can be rebuilt using the appropriate recovery tools and, to date, none of our customers have reported a recurrence of the problem.