If you need to return to a previous operating system that does not support the NTFS file system, you need to remove the NTFS C: partition.
NOTE: Copy any files that you need to preserve to a partition that can be read by the operating system you intend to install.
Method 11. Boot the Windows NT or Windows 2000 Setup media and begin an install.
2. When offered, delete the C: partition.
3. Proceed for a 2 or 3 more screens before you abort Setup.
4. Follow the procedure for installing you previous operating system.
Method 21. Download the Delpart.exe DOS based utility that is included in the Windows NT 3.1 Resource Kit at ftp://ftp.microsoft.com/bussys/winnt/winnt-public/reskit/nt31/i386/reskit.exe.
2. Double-click the reskit.exe file and extract the files. Discard all the files except Delpart.exe, which you should copy to a DOS boot floppy. If you don't have a DOS boot floppy, see How do I boot to DOS to flash my BIOS if I only have Windows 2000?
3. Boot the DOS boot floppy and sys C: the drive to restore a DOS boot sector.
4. Run Delpart.exe. The following is from the RKTOOLS.HLP file that I extracted from reskit.exe:
DelPart deletes one or more partitions, including NTFS partitions. This allows you to remove an NTFS partition without reformatting your hard drive. (You cannot use the MS-DOS fdisk command to remove NTFS partitions.)
DelPart deletes whole partitions, and also can delete individual logical drives in extended partitions.
To use DelPart:
At the command prompt, type delpart
Important: DelPart also provides full UNDO capability. You can delete all partitions on a hard disk, and physically write that information out, then choose Edit Undo and be able to restore the hard disk partitioning scheme back to what is was before DelPart was run.
Note: You can also delete partitions by running the Windows NT Setup program from disks, CD, or the network. You can quit Setup after completing the early steps to delete partitions or create new ones.
File required for DelPart:
5. Follow the procedure for installing you previous operating system.