| The BIOS (Basic Input/Output System) in a | | | | The 55AA is known as boot signature and work |
| Microsoft Windows computer is a boot firmware, | | | | like an EOF (End Of File) when the process reads |
| which provides all of the boot information to | | | | the sector. Damaged or missing (due to operating |
| computer processor for proper booting of your | | | | system malfunction, software errors and |
| system. In the first physical sector of BIOS, MBR | | | | improper system shutdown) boot record |
| (Master Boot Record) is stored. MBR loads the | | | | signature can cause severe issues. In such case, |
| first sector of your boot media, either hard drive | | | | the data stored in the hard drive partition table |
| or floppy. After successfully loading first sector, | | | | gets damaged and your system becomes |
| BIOS examines last two bytes of the boot sector | | | | completely unbootable. |
| (that is 55AA). | | | | |