Windows 8 and 8.1 Forums


Uninstall OS [Dual Boot]

  1. #1


    Posts : 2
    Windows 8 Pro x64 RTM

    Uninstall OS [Dual Boot]


    Hi guys,

    I have running two OS Windows 7 / Windows 8 x64 RTM in same HDD. I want to uninstall Windows 7 i know that i can do it from disk managment by delete Windows 7 part at i am on Windows 8.

    But What should i do additional for save or make Windows 8 properly ?

    Edit:----------------------------------------------------------------------------------------------

    Guys I already done it !

    I first opened msconfig and made Windows 8 as a default OS. Than i delete Windows 7 boot entry and make it click parment settings at same tab. After that i deleted the partition from disk managment at Windows 8 and extend Windows 8 partition with Partition Wizard[freeware] software.

    Now i am happy with Windows 8 Pro RTM x64.

    [Did not need EasyBCD or something like that, Windows 8 is newer OS than Windows 7 i think thats why...]
    Last edited by mstf008; 06 Aug 2012 at 15:16.

      My System SpecsSystem Spec

  2. #2


    Sofia
    Posts : 135
    XP, Win7, Win8_Eval


    Uninstalling Win 7 = (is equal to)
    1. Delete boot menu entry for Win 7
    2. Delete partition of Win 7

    BUT: you cannot delete an active partition (where the boot files are) !

    If Windows 7 partition is active you have to:
    A) mark Win 8 partition active (use Disk Management)
    B) reboot Win 8 installation media (DVD/USB) and run up to 3 consecutive times "Start-Up Repair" with rebooting after each run.

    To remove boot entry for Win7 - you can use Visual BCD Editor:
    Click on loader for Win 7 (in left pane), right-click and select "Delete object/loader".
    Last edited by boyans; 06 Aug 2012 at 01:23. Reason: added how to remove boot entry
      My System SpecsSystem Spec

  3. #3


    You can delete the Windows 7 partition, but you are gonna be left with space you cannot use. Windows 8 should boot properly, if it doesn't simply use the windows 8 installation CD and click "Repair my computer" -> choose your partition -> click cancel so you don't reboot -> Choose advanced options -> command prompt. In the command prompt run the following commands.
    1. bootrec.exe /fixmbr
    2. bootrec.exe /fixboot
    3. bootsect.exe /nt60 C:


    To reclaim lost space follow this.
    WARNING, may cause data loss.
    Get Gparted here (It's a linux partition manager)
    Use unetbootin or burn gparted to a CD
    Boot into your usb or CD and choose gparted (default)
    If it asks you anything just press enter (everything is default)
    At the end you should be taken to a desktop. Wait a few moments and a window should pop up.
    If you havn't deleted your windows 7 partition yet delete it now.
    Right click your windows 8 partition and click resize/move.
    Expand the drive until there is no gray. (Gray is empty space/where your windows 7 used to be)
    THE PROCESS WILL TAKE A LONG TIME (1-2 hrs) DO NOT CANCEL OR IT WILL BE CORRUPTED
    at the end you may need to repeat the process of fixing your disk stated in the first paragraph.
      My System SpecsSystem Spec

  4. #4


    Sofia
    Posts : 135
    XP, Win7, Win8_Eval


    @XDleader555
    1. bootrec.exe /fixmbr
    2. bootrec.exe /fixboot
    3. bootsect.exe /nt60 C:
    This is not enough to make a system bootable.
    - In quote -> 2. is almost equal to 3. and 1. is redundant
    - There is no command for creating a BCD and other boot related files.

    For making another partition bootable (only NT6 based OS's installed):

    1. It is very important to make the new boot ("system" in M$ tems) partition ACTIVE !
    On command prompt diskpart.exe can be used to mark a partition active.
    Select disk, then partition, then make active:
    diskpart
    a) select disk 0,
    b) select par # (# is partition number),
    c) active
    exit

    2. MBR is already there (but we can rewrite with next command)
    3. bootsector /nt60 all /force /mbr
    4. bcdboot drive_letter:\windows - where drive_letter is drive where the latest Windows OS is installed.

    Latest Windows version is Windows 8 then Windows 7 then Vista (Windows NT 6.2, 6.1, 6.0)
      My System SpecsSystem Spec

  5. #5


    Quote Originally Posted by boyans View Post
    - There is no command for creating a BCD and other boot related files.
    I forgot, if you need to rebuild the BCD you can use bootrec.exe /RebuildBcd, although, I havn't had much success with this command. I found that if you copy the boot files from the old partition/harddrive to the new one it will boot when it's marked active. (BCD editors won't work anymore though)
      My System SpecsSystem Spec

  6. #6


    Sofia
    Posts : 135
    XP, Win7, Win8_Eval


    I found that if you copy the boot files from the old partition/harddrive to the new one it will boot when it's marked active. (BCD editors won't work anymore though)
    What would be the reason for BCD editors not to work anymore ?
    Can you explain your thoughts or reasoning about this topic ?
      My System SpecsSystem Spec

  7. #7


    Quote Originally Posted by boyans View Post
    I found that if you copy the boot files from the old partition/harddrive to the new one it will boot when it's marked active. (BCD editors won't work anymore though)
    What would be the reason for BCD editors not to work anymore ?
    Can you explain your thoughts or reasoning about this topic ?
    I used to have a dual boot of windows XP and windows 7. I decided to remove windows XP by deleting the partition, but the windows 7 boot files were located on that partition. By copying my BCD to the windows 7 partition and marking it active allowed me to boot into windows 7 while the windows XP partition is gone. I then tried to remove Windows XP from the BCD with a bcd editor and msconfig, but it didn't find the BCD anymore.

    Why did I have XP an 7? idk. Why were my BCD files located on windows XP? idk ._.
      My System SpecsSystem Spec

  8. #8


    Sofia
    Posts : 135
    XP, Win7, Win8_Eval


    The BCD is just a registry file.
    If bootmgr can read it (during successful boot) I don't see a reason it is unreadable for other (system)programs.
    The only reason could be security privileges.

    To avoid security problems when copying a BCD use import/export functionality of bcdedit or ensure copy of all security settings for the file. (At least "SYSTEM" and "Administarators" should have full read/write access.)
      My System SpecsSystem Spec

  9. #9


    Posts : 2
    Windows 8 Pro x64 RTM


    Guys I already done it !

    I first opened msconfig and made Windows 8 as a default OS. Than i delete Windows 7 boot entry and make it click parment settings at same tab. After that i deleted the partition from disk managment at Windows 8 and extend Windows 8 partition with Partition Wizard[freeware] software.

    Now i am happy with Windows 8 Pro RTM x64.

    [Did not need EasyBCD or something like that, Windows 8 is newer OS than Windows 7 i think thats why...]
      My System SpecsSystem Spec

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