This fdisk command will allow you to recreate the Master Boot Record or MBR on systems running WIndows prior to XP. Although this can be dangerous, it is a quick way to fix many boot issues.
This is for Windows systems before XP. Follow these directions for restoring MBR on XP systems.
1. Click Start
2. Click Run
3. Type CMD and hit ENTER
4. From this dos box command line:
FDISK /MBR
This rebuilds the boot sector of the first bootable hard disk based on current disk structure. The partition table information should not be altered.
This is usually used to repair a damaged, corrupted, or infected master boot record.