How do I remove Windows95/Dos from my NT system?

Modify the attributes on boot.ini to allow the file to be edited
attrib c:boot.ini -r -s

Using Notepad (or another test editor open c:boot.ini and remove the lines for DOS and/or Windows95 from the [operating systems] section, e.g. the lines to remove may be
c:="MS DOS 6.22"
c:bootsect.622="MS DOS 6.22"
c:="Windows 95"

Lines to avoid removing are structured like
multi(0)disk(0)rdisk(0)partition(2)WINNT="Windows NT Workstation Version 4.00"

Save the file, and put back the file attributes
attrib c:boot.ini +r +s

If you are removing DOS then delete the DOS tree structure
deltree c:dos

If you are removing Windows95 then delete the Windows 95 tree structure ** Make sure it is not the same directory as NT is installed in, this is very unlikely however **
deltree d:window95

You will also need to remove applications that were only installed for use with Windows 95/DOS, e.g. programs under Program Files, however NT will also install applications in this directory so be careful.

DOS and Windows95 place a number of files on the boot partition that can be deleted, e.g.
- autoexec.bat
- config.sys
- IO.SYS
- MSDOS.SYS
- bootlog.txt
- command.com
It will probably be safer to copy them somewhere before deleting them and just check NT boots OK. You may need to set them to be deletable using
attrib -r -h -s
You can basically delete all files at the base of the boot partition except
- boot.ini
- ntldr
- ntdetect.com
- ntbootdd.sys (for SCSI systems)
Which are needed for NT startup

Reboot the machine and Windows95/DOS are now removed