Repair Windows 7 Boot Loader Problem

The first thing you’ll need to do is boot off the install disc, and then click through until you see the “Repair your computer” link in the lower left-hand corner.
You’ll need to choose the correct installation of Windows and then click the Next button.

And then you’ll get to the System Recovery Options screen, where you can get to the Command Prompt.

Repairing the Master Boot Record

If you want to restore the master boot record, you can simply type in the following command:

bootrec /fixmbr

You can also write a new boot sector onto the system partition with this command (which is often more useful):

bootrec /fixboot

And of course, if you just use bootrec /? you’ll be able to see all the options.

This is the same way that we fixed the “BOOTMGR is missing” error when trying to boot up Windows 7 or Vista.

Replacing the Windows XP Bootloader with Windows 7

If you’ve managed to install XP on the same PC that you already had Windows 7 on, you’ll noticed that you can’t boot into Windows 7 anymore. You can use this command to fix that and restore the Windows 7 bootloader:

bootsect /nt60 all

Depending on the partition that you’ve installed, you might need to substitute the drive letter instead of “all”.

Note: if you want to restore Windows XP back to the menu, you can open up a command prompt in Windows 7 and run this command:

bcdedit /create {ntldr} -d “Windows XP”

Using the Automated Startup Repair

Of course, all this command-line stuff is probably not necessary in most cases. You can usually just use the Startup Repair option from the Recovery menu…

It’ll check for problems and probably fix them. If not, then you can always use the command prompt.