OK, I've never tried this specifically (deleting NT from
a dual-boot 95 & NT machine), as my usual mode
of operation for changing uses on a machine is format /u c:,
or better yet, mke2fs /dev/hda1, so be forewarned...

Basically, the hard drive on the PC has what is called
a master boot record. This is the thing that the PC BIOS
calls when it first powers up. Usually that contains some
basic sort of bootstrap loader, that is either dedicated
to a single operating system (e.g. the one used by DOS),
or is able to handle multiple operating systems on the
same machine (e.g. the ones that come with NT, OS/2 and
Linux; additionally "System Commander" and "Partition
Magic" may have their own bootloaders, I've never used them.

In addition to this, the operating systems are installed
on partitions of the disk (you knew this). The boot
partition for each operating system will usually have
second-stage bootstrap code in a specific boot block for
the partition. The first-level master boot record will
branch to the boot block in the partition that contains
the operating system that you want (or don't want, if
it's a bad day) to boot. If you are using the DOS master
boot record, it goes to the boot block of the active
primary partition on the first hard disk in BIOS order,
beginning and end of story. Other master boot records
are more functional and will present you with a menu
on the display, from which you can select the desired
OS, in your case MS-DOS 7.0 and Windows NT. Windows 95,
being DOS based, will of course be living in the C:
drive, and NT will be somewhere else.

To get rid of NT, there are two cases: (a) you used
NTFS and (b) you didn't. Case (b) should be easier;
I believe that all you should have to do is to:

  * Boot to DOS. Simplest way is to boot from a
    DOS boot floppy.

  * Make sure that you have a copy of fdisk available
    after you boot in DOS mode, and then run
    the command "fdisk /mbr". This is the magic
    incantation that will replace whatever is in
    the master boot record with the disfunctional thing
    that DOS usually uses and works best with.

  * Run fdisk again, this time without arguments. Select
    the boot drive, and *make sure* that the DOS boot
    partition is set as the active partition.

  * Reboot.

I believe that this is all there should be to it, but
I could be wrong. If this works, you should then be
able to format the NT partiton and/or re-use it for DOS
stuff. The main problem with this is that NT may have
placed some crud in your C: drive, and some of it
(I'm on really shaky ground now, so get out that box
of salt) may have been damaged some of your DOS boot
stuff. But I don't think so because your DOS partition
was still bootable when called from the NT bootloader.

In the case that you *had* used NTFS, it is just a little
harder. The process should be the same, except that
you won't simply be able to reformat or reuse the old
NT partition. Also, some versions of fdisk are crippled
so that they will refuse to remove or alter partitions
that do not contain DOS filesystems. If you use fdisk
and it tells you about a non-DOS partition, and gives
you a hard time when you try to delete it, then you
are kind of stuck a little; you'll need something else
to get rid of it. It is problematic attempting to
remove the partition from NT before doing the fdisk /mbr,
because NT will refuse to remove itself. :-(

The main solution in this case is to get a disk partition
program that will delete it for you. Two good, free
alternatives are (a) any Linux rescue disk or "tiny"
distribution, or (b) Caldera's DR-DOS 7.02, available
for download from ftp://ftp.caldera.com/pub/drdos/DR-DOS.702.
download and create the first boot/install floppy,
open the floppy on your existing machine and remove
the autoexec.bat (or press an F5 when it boots in the
next step.) Boot from that floppy, then run fdisk in extended
mode (I think fdisk /x).  This version of fdisk knows about
all kinds of partitions, even Linux and NT partitions,
and will let you wreak havoc on your machine if you like.

Once you've deleted an NTFS partition, don't immediately
create a DOS partition to replace it. Reboot to the
version of DOS (e.g. Windows 95) that you are going
to be using, and have it's fdisk create the partition.
Depending on the version of fdisk that you used to rid
your machine of the NTFS partition, this may not strictly
be necessary, but being conservative in this step should
always work. Some versions of fdisk (especially some
Linux versions) will fail to emulate some of DOS's
endearing bugs, and you may not be able to use the
partition from DOS/Windows when you're done. Thus, it
us usually better to just use the regular DOS fdisk
to create your DOS partitions.

Hope this helps,

--Bob


On Fri, Feb 12, 1999 at 03:11:10PM -0800, Andre Abelian wrote:
> Hi to all engineers,
>
> In my PC I have 95 and NT installed with dual boot.
> since I do not use NT anymore I was wondering if there is
> a way to uninstall NT. any idea  will appreciate.
>
>
> Andre

--
============================================================
Bob Drzyzgula                             It's not a problem
bob@drzyzgula.org                until something bad happens
============================================================