Master Boot Record: The 512-byte boot sector that is the first sector (”Sector 0″) of a partitioned data storage device such as a hard disk.

A Windows Vista-based computer does not start because the master boot record (MBR) has been corrupted. When you try to use the Startup Repair tool to fix the MBR, the Startup Repair tool reports that no problem was found.

Note: You can access the Startup Repair tool on the Windows Vista installation disc.