How to uninstall GRUB from the MBR (Master Boot Record) of the hard disk.
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As GRUB does not make any backup of the MBR during the installation, it can only be uninstalled by overwriting the MBR with another boot manager. Therefore, the MBR must be rewritten using a different operating system.
Using a DOS or Windows 9x / ME Boot Floppy
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In case you have DOS or Windows 9x / ME on your system, you can use fdisk for this purpose. Create a rescue disk in DOS or Windows 9x/ME, use it to boot the computer, and execute fdisk as follows:
fdisk /mbr
The MBR will be rewritten and GRUB will be uninstalled.
Using an OS/2 Boot Floppy
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If you use OS/2, the corresponding command is:
fdisk /newmbr
Using Windows XP
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Boot from the Windows XP CD and press the "R" key during the setup in order to start the Recovery Console. Select your Windows XP installation from the list and enter the administrator password. At the input prompt, enter the command "FIXMBR" and confirm the query with "y". The MBR will be rewritten and GRUB will be uninstalled. Press "exit" to reboot the computer.
Using Windows 2000
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Boot from the Windows 2000 CD and press the "R" key during the setup and the "K" key in the following menu in order to start the Recovery Console. Select your Windows 2000 installation from the list and enter the administrator password. At the input prompt, enter the command "FIXMBR" and confirm the query with "y". The MBR will be rewritten and GRUB will be uninstalled. Press "exit" to reboot the computer.
The process described above is applicable to both LILO and GRUB.
Note that in case of LILO, there is the additional option of uninstalling it from within linux by running (as root)
CODE
lilo -u