Vista or Winodws 7 - MBR Boot problems

     Sometimes a virus knocks out the Master Boot Record MBR and you have to repair it.  I have found that when you have a drive with multiple partitions the record is not always fixed with the correct drive letter.  Example my vista machine was not booting to drive F not C and all of the registry entrys were looking for C so it was not loading all the profiles correctly.  To fix this I used these steps.


Boot from a ERD disk for factory disk in recovery mode

goto Command prompt and reset the MBR

I used

Bootrec /fixmbr
Bootsect /nt60 all /force

then I typed

Bootsect /nt60 all f: /mbr /force

so it would boot to the F drive


When vista loaded I need to switch the drive letters around so I loaded the registry using control alt delete and running task manager then using the run command typed regedit

1. Go to the following registry key:

2. Export the entire key MountedDevices

look for lines like this using notepad



3. Now switch everything after the hex: from one to the other making sure no extra spaces

should look like this



4. Re-import the file (dblclick on the reg file) and reboot.  your F drive should now be C Drive

Note:  to reboot I held the Power Button until it turned off then powered back on

Also saw a command to use bootrec /rebuildbcd but have to use factory disk not ERD disk to repair the BootRecord  they want you to also rename the c:\boot\bcd file

Larry said to use bootrec /fixmbr


/bootrec /fixboot

to fix master boot records.  Did not work for me.

XP Switching Drive

1. Go to the following registry key:

2. Export the entire key MountedDevices

3. on the right find the two drives you want to switch and right click on the \DosDevices\C: and choose rename

rename to \DosDevices\X:

find the other drive \DosDevices\I: and rename to \DosDevices\C:

rename the \DosDevices\X: back to the \DosDevices\I:


If you need to change the entrys in the registry to match the new drive letter you created you will need this program to edit the registry to do a global search and replace.  grab the 32 bit registry program or click here for file

Do this before you reboot.

4. load the regkt program

click on Registry and click on Search and replace

Enter in the Search for I: and Replace with C:

the replace button at the bottom

5. Exit the program open regedt32 and import the file that was created with the regkt program
(DO NOT DOUBLE CLICK THE FILE) it will merge the data you need it to replace the date using the import! 
Have Fun.  Just worked for me!


Interesting article on BCD Boot Mgr

PS not responsible for this not working or any damage it may cause! Cloan the original drive 1st for a backup.
Work from the cloan. Cloan it back if it works

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