How to fix MBR through command prompt?

Did you try setting H hard drive as the first HD in bios boot order - mark the 7 partition Active - run startup repair 4 or 5 times.

I don't want to send this off in the wrong direction or give bad info.
But I can tell you what I would try personally in this situation.

If the MBR is toast, then you may have no other choice than to nuke and reload

I do not know if these will work or be compatible with Win7 in anyway shape or form, or if OS version even matters...This could make things better or worse.. So, use at your own risk...

You can however try MBRFix and/or MBRWiz

You can also possibly try TestDisk, which is a data recovery program.
And has save my butt a few times.

I do believe both are a part of the UBCD4Win (however you would also need to upgrade some tools plugins as they may be out dated), which you may find very handy in this or many other situations. Every Tech should be aware of it and BartPE (which UBCD4Win is a derivative of).

With all that said.....

You can try DiskPart also....to assign the drive letter you want.
http://technet.microsoft.com/en-us/l...8WS.10%29.aspx
http://support.microsoft.com/kb/300415

I would start with building a UBCD4Win (or BartPE) and boot to it, see if the drive shows up in Drive manager.

If it does, I might try changing the drive letter there, then set as active.
Then if needed run some of the 7 boot option fixes to see if this will repair any BCD problems.

I say might, because I have never had to do this, this would just be a way I would go if all else was failing.

If the drive is not showing up at all in there, then the MBR is toast and you can try the MBRFix or MBRWiz to try and repair it if possible. If these fail, then you can try TestDisk, this may work, but is not likely, however, it may allow you to recover data id it finds it.

If all this fails, with all else you have tried, Personally, I would give up the ghost and nuke and reload.

Once the MBR is toast, there is almost no way to fix it.

Although, someone may know something I don't.

Tepid said:

Just a little warning to those who may not know....

Playing with the MBR is a risky thing.
If you don't know how to recover data and haven't done/or don't know how to do a backup.
Then you shouldn't be messing with the MBR at all.

Simply running /fixmbr can and has corrupted it for me several times in the past.
This is not something that a simple windows repair can usually fix, usually.

I had a backup so I just decided to re-install. Windows 7 is fast to install I backup & running within 1 hour.

thanks everyone.

I am just reading so many different questions and answers. thanks to all.

Hello,

One of my computers does not want to start or restart but only SOMETIMES.

Do you think that FixMbr or FixBoot could help ?

Or because this computer often starts without problem it should not be of any help ?

Thank you.

If getting the "Total identified Windows installations: 0" when running bootrec /scanos, eg:

X:\windows\system32>bootsect.exe /scanos
Scanning all disks for Windows installations.

Please wait, since this may take a while...

Successfully scanned Windows installations.
Total identified Windows installations: 0
The operation completed successfully

You'll need to clean the MBR then create a new MBR and tell Windows to use it. To do this, simply run these two commands:

bootrec /fixmbr

bootsect.exe /nt60 all /force

You should see a message that says your "Bootcode was successfully updated on all targeted Volumes"

This helped me when i had to delete my linux partition and the separate MBR partition due to not enough space on windows. After extending the windows partition to the newly formatted NTFS partitions I obviously did not have an MBR anymore. The "fix problems preventing windows from starting" did not work and none of the commands in this forum worked. I used a bootcd to get into command prompt and ran this & it fixed it right away. Hope this helps you if you're having the same problem