To remove an installation from a Dual/Multiple Boot installation. Warning:

Editing a dual-boot systems can cause a loss of existing data and programs . I would suggest to completely back-up everything that matters to you before you try to remove part of a dual-boot system. If things go wrong you might be unable to boot to any of your partitions. You do this at your own risk.

Removing Windows NT from a Windows 95/98 Dual-Boot Installation

This article describes how to remove the Windows NT Boot Loader to remove Windows NT from a dual-boot installation with Windows 95/98 and leave Windows 95/98 as the bootable operating system.

Following these steps may lead to data loss if your computer currently has a virus or you have disk-management software installed on your hard disk (such as OnTrack Disk Manager or Micro House EZDrive) to allow you to access a larger hard disk than your computer's BIOS supports.

The following steps apply only to computers in which the boot drive (drive C) uses the FAT file system and Windows 95/98 is installed on the boot drive.

-Back up the critical data on your hard disk, and verify that the computer is not infected with a virus.
-Boot the computer with your Windows 95 Startup disk. If you do not have a Startup disk, you can create one. In Windows 95, double-click Add/Remove Programs in Control Panel, click the Startup Disk tab, and then click Create.
-At the "A:" prompt, type sys c:, and then press ENTER. You should see a "System transferred" message.
-Remove the Startup disk from the floppy disk drive, and then restart the computer. Windows 95 should start.
-If you have completed the above steps successfully, you can remove the folder containing Windows NT (typically C:\Winnt).
-You can delete the following files from the root folder:

Ntldr
Ntdetect.com
Boot.ini
Pagefile.sys (if present)
Bootsect.dos


All of these files except Ntldr are hidden. To view them, start My Computer, click Options on the View menu, and then click Show All Files. To view file name extensions, click the "Hide MS-DOS extensions for file types that are registered" check box to clear it. Click OK.

Removing a Failed win XP Installation

When there is already another working OS on the system, or that the new XP installation was an upgrade.

-put the XP cd in the cd drive

-boot up the computer into safe mode with command prompt only (press delete, F8)

-type cd E:\ where E is the drive letter of your cd drive

-type cd \windows\system32 to get into system32 directory

-type osuninst.exe to start the uninstallation

-follow the instructions in the onscreen menu to remove or revert your Windows installation.

Removing a Dual Boot WindowsXP installation (XP and XP or Prior windows)

This will remove the boot option screen and allow the removal of extra windowsXP installation

right click on my computer icon
click on properties
click on advanced tab image 1
click on settings button under startup and recovery image 2
here you can choose default operating system at system start up and also change the time to display list of operating systems.

-in the new dialog box you have a couple of options:
-if you wish to leave DOS on the machine, but not see the option screen you can simply set the 'time to display list of operating systems:' to 0 (zero) as winXP should now be the default OS
-if you want to removal the Dos or the additional XP , then click edit
-first save a copy of the notepad file which opens 'boot.ini' to have a backup.

look into the file for entries similar to ones below

[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0) disk(0) rdisk(0) partition(1) \WINDOWS = "Microsoft Windows XP Home/ Professional" /fastdetect /NoExecute = OptIn

There will also be a line for dos under [operating systems]
'multi(1) disk (0) partition (#).....'
-check that your default line points to XP, as it does above
-now erase the line with the other OS, DOS 7.1 or the extra WindowsXP ie. 'multi(1)'
(the entire line may span more than one line in notepad)
-save the file

-reboot your system

-if you encounter any problem load into either DOS or XP and copy the old boot.ini over the modified one, and try again

-now at the end you can delete the folder associated with the windowsXP installation you want to remove from the hard disk, make sure you are deleting the right folder.

How to Uninstall Vista on Dual Boot Machine (XP and Vista)

if you have vista on your dual-boot As vista has its own bootloader, you'll need to follow these steps to remove it. Dual-booting with vista can be a little tricky to remove because of the new bootloader.