DOCUMENT:Q92383  02-NOV-1993  [W_NT]
TITLE   :Problems Installing Other Operating System after Windows NT
PRODUCT :Windows NT
PROD/VER:3.10
OPER/SYS:WINDOWS
KEYWORDS:

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The information in this article applies to:

 - Microsoft Windows NT operating system version 3.1
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SUMMARY
=======

After you successfully install Windows NT version 3.1, Microsoft does
not recommend that you install other operating systems on the same
computer.

MORE INFORMATION
================

When Microsoft Windows NT is installed over a previous operating
system, it copies the contents of the boot sector to a file called
BOOTSECT.xxx in the root directory. The extension of this file is
determined by the previously installed operating system; in the case
of MS-DOS, the extension would be .DOS; in the case of OS/2 version
1.x, the extension would be .OS2. It then copies a Windows NT startup
utility called the Boot Loader into the boot sector.

When the system is restarted, this utility presents you with a choice
of which operating system to start. Once you have made your selection,
the Boot Loader locates either the Windows NT bootstrap or the
BOOTSECT.xxx file, and turns over control.

If you install another operating system or upgrade to another
operating system after installing Windows NT, that process generally
replaces the Boot Loader in the boot sector, destroying the dual boot
opportunity, and effectively preventing Windows NT from starting
(booting).

To recover from this, you can use the Emergency Repair Disk. Choose
Verify Boot Files from the main menu.

Note: MS-DOS 6.0 upgrade leaves the NT Boot Loader intact--MS-DOS 6.0
OEM Setup does not.

Additional reference words: 3.10 win32 boot setup winset overwrites
KBCategory:
KBSubCategory: INTROP

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Copyright Microsoft Corporation 1993.