Issues with Removing Windows 2000 and Reinstalling Windows NT 4.0 (257754)

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The easiest method to remove Windows 2000 from your computer and reinstall Windows NT 4.0 is to back up any data and files that you need to keep, reformat and repartition all drives, install Windows NT 4.0, install the latest Windows NT 4.0 service pack, install your programs, and then restore your data.

NOTE: If the size of the boot and/or system drive exceeds 7.8 gigabytes (GB), you need to repartition the drive (this is a limitation in Windows NT 4.0 Setup). Also, any drives that are formatted with the FAT32 file system need to be removed or reformatted.

For additional information about these issues, click the article numbers below to view the articles in the Microsoft Knowledge Base: Before you remove Windows 2000 from your computer, review the following topics:

• Backing up data
• NTFS considerations
• FAT32 considerations
• Encryption
• Profiles issues
• Boot sector
• Deleting files and folders
• Dynamic disks

Backing Up Data

Before you remove or install an operating system, back up all data files in the computer to prevent accidental file deletions. This becomes particularly important when you have FAT32-formatted partitions, because these partitions are not available under Windows NT 4.0. Also, there are some NTFS file system limitations after you upgrade your computer to Windows 2000. Copy all data files to a network share or removable media, or back them up by using a backup program that is compatible with both Windows 2000, and Windows NT 4.0. After you reinstall Windows NT 4.0, the latest service pack, and any programs, you can restore the data.

For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

NTFS Considerations

When you install Windows 2000, all NTFS volumes on your computer are upgraded to the version of NTFS that is included with Windows 2000. Although Windows NT 4.0 Service Pack 4 or later enables read and write access to these drives, there are some limitations. Utilities such as Chkdsk that are included with Windows NT 4.0 do not work properly, and you can only obtain access to the Repair and Chkdsk utilities included with Windows 2000 while you are running either operating system, or when you are running Recovery Console for either operating system. Some enhanced features such as Encryption or Reparse Points are not available, and files that are encrypted or contain reparse points are not accessible under Windows NT 4.0. For these reasons, Microsoft recommends that you back up all data and then reformat these NTFS drives during Setup or after you install Windows NT 4.0.

NOTE: You cannot set up boot and system drives that are formatted with NTFS by using Windows NT Setup because of upgrades implemented by Windows 2000 on all NTFS drives. The driver in Windows NT 4.0 Service Pack 4 and later enables you to read and write to NTFS drives, however, there is no way to place this driver into the Windows NT 4.0 Setup process. Because of this, the NTFS driver in Windows NT 4.0 is not able to properly read or write from NTFS drives upgraded by Windows 2000. There is no workaround to this issue. Note that NTFS data drives become available under Windows NT 4.0 after you install Service Pack 4 or later.

FAT32 Considerations

Windows 2000 supports the FAT32 file system but Windows NT 4.0 does not. FAT32-formatted partitions are not available under Windows NT 4.0, and data on these partitions is not accessible unless you are dual-booting with another operating system that supports FAT32, such as Microsoft Windows 98. The system drive (the drive that contains the boot files) and the boot drive (the drive that contains the Winnt folder) cannot be a FAT32-formatted partition. You should back up all data located in FAT32 partitions, and then format them with either FAT or NTFS. You can do this either during Windows NT 4.0 Setup or later. Note that NTFS-formatted drives must be reformatted as NTFS under Windows NT 4.0. See the section on NTFS considerations.

Encryption

Windows 2000 supports the encrypting of files on NTFS drives but Windows NT 4.0 does not. Files encrypted under Windows 2000 are not available under Windows NT 4.0. You must decrypt these files before you back them up so that they are be available after you reinstall Windows NT 4.0.

Profiles Issues

Profiles are stored by default in different locations in Windows NT 4.0 and Windows 2000. The default location for profiles in Windows NT 4.0 is the SystemRoot\Profiles folder. In Windows 2000, the default location is the SystemDrive\Documents and Settings folder. However, if you upgraded from Windows NT 4.0, the profiles are still located in the SystemRoot\Profiles folder. Profiles usually contain some data files and possibly other information that may be needed; deleting the SystemRoot folder when you remove files may delete these files. Because of this, it is important that you back up these files first.

Boot Sector

If you do not repartition or reformat the system drive, and you do not install Windows NT 4.0, the boot sector may still be on the drive. This is not an issue if the drive is formatted with the FAT file system. However, if you reinstall Windows NT 4.0, the Windows 2000 boot sector may be overwritten. If not, you can run the Windows NT 4.0 Repair process and choose to overwrite the boot sector. In most cases, Microsoft recommends that you boot with a Windows 98 or Microsoft Windows 95 Startup disk first, and then run the sys command on the drive before running a Repair process or installing Windows NT 4.0.

Deleting Files and Folders

If you repartition or reformat the drives, some of these files and folders are not present. There will be files on the system drive (the drive that the computer boots from) and there will be files and folders on the boot drive (the drive that contains the SystemRoot folder, usually the Winnt folder). These two drives/partitions can be the same location or they may be on separate volumes. Before you delete any folders, verify that you have a good backup of any files that you want to have available after you reinstall Windows NT 4.0. If you delete these files, Windows 2000 is unavailable. You must have the Boot.ini, Ntldr and Ntdetect.com files from Windows NT 4.0 to boot Windows NT 4.0.

On the System Drive

• Ntldr
• Ntdetect.com
• Boot.ini
• Recycle Bin

On the Boot Drive

• The SystemRoot folder in most cases is the Winnt folder, by default (this is the folder in which Windows 2000 is currently installed)
• The Program Files folder
• The Documents and Settings folder, unless you upgraded from Windows NT 4.0
• The Pagefile.sys and Hiberfil.sys files (if hibernation was enabled on the computer)

Microsoft recommends that you install Windows NT 4.0 in its own partition, not in a partition that contains an installation of Windows 2000. However, there may be cases where this is not possible, or installing Windows NT 4.0 back on your computer may be time critical. If you have only one partition available, and if this partition has sufficient disk space for the installation, use the following procedure:

1. Start Windows NT 4.0 Setup by using the Winnt32.exe program included with Windows NT 4.0 Service Pack 4 or later. If this program is not available, boot your computer by using a Windows 95 or Windows 98 Startup disk, and then type sys c:, where c is the drive that you boot from.
   
   You may experience a reboot loop because of a problem with the Windows NT 4.0 Setup program if Windows 2000 was installed. Removing the Windows 2000 boot sector and replacing it with an MS-DOS-based one or by using the Winnt32.exe program that is included with Service Pack 4 or later resolves this issue.
2. If you install Windows NT 4.0 in a folder other than the Winnt folder, you do not need to rename the Winnt folder. However, if you want to use the same folder name, you must rename the Winnt folder. For example, type ren winnt win2000 at a command prompt, and then press ENTER. This command renames the Winnt folder to "Win2000". Note that after you do this, you will not be able to reuse Windows 2000.
3. Rename the Program Files folder by typing ren "program files" "old program files" at a command prompt, and then pressing ENTER. Because Windows NT 4.0 and Windows 2000 use the Program Files folder, this folder must be renamed if you are installing Windows NT 4.0 on the same drive and you do not want to delete the folders at this time. If the Hiberfil.sys file exists, you can delete it; this file is not used in Windows NT 4.0.
4. The Documents and Settings folder is not used by Windows NT 4.0 and is not overwritten. It will be available after the upgrade unless you format or partition the drive during Windows NT 4.0 setup.

After you rename the two folders and replace the boot sector with one from the Windows 95 or Windows 98 Startup disk, you can install Windows NT 4.0. You should have the three Windows NT 4.0 boot floppy disks to start Windows NT 4.0 Setup. If not, you can boot by using a Windows 98 Startup disk or a bootable disk that contains your CD-ROM drivers, and then run Winnt.exe. This copies the files from the CD-ROM to the local hard disk and creates the three boot floppy disks.

NOTE: If you boot with a Windows 98 Startup disk, run Smartdrv to help speed up file copying.

Dynamic Disks

Windows 2000 supports dynamic disks but Windows NT 4.0 does not. Convert dynamic disks to basic disks before you remove Windows 2000 and install Windows NT 4.0, otherwise they will not be available under Windows NT 4.0.