|19H bootloader is a software interrupt generated by the BIOS to initiate the routine that loads the boot loader from the hard disk. If it cannot complete its task the OS will not load. It is a hard disk error.|
Go to the drive manufactures web site and download a diagnostic for the drive. The chances are the drive is toast and may need to be replaced. At best it will need to be repartitioned and that means losing all the data on the disk.
I hope you have backups.