In some cases you need to edit/repair Windows boot, for example if you have a dual boot Linux/Windows and want remove Linux or when some programs modify boot adding new boot entries (generally to start these programs in a safe environment).
The first, available for free by choosing the Community Edition version, allows to easily edit the boot and add new boot entries or delete existing ones.
Another useful feature is the BCD (Boot Configuration Data) Backup/Repair.
The other program, for Windows 7, 8, Vista, XP has a simple menu that allows: repair BCD, backup/export BCD, restore/import BCD, repair the MBR, this is very useful when you don’t have the original Windows installation disc that allows to repair the Master Boot Record.
These software works in Windows, but if the operating system doesn’t start because the boot has problems what you can do?
You can use another free software, AOMEI PE Builder that allows to create a bootable disc/USB based on Windows PE (Preinstallation Environment). It has various utilities, included BOOTICE, it allows to manage the boot and also restore it.