If you wish to prevent the Exchange client from being installed when you install Windows NT 4.0:

1. Copy the i386 folder to the HD of a Windows NT system.
2. Switch to that folder and type: expand Syssetup.in_ Syssetup.inf
3. Rename Syssetup.in_ to Syssetup.old
4.Edit Syssetup.inf and replace MSMAIL.INF in the \[BaseWinOptionsInfs\] section with ;MSMAIL.INF

When you install from this folder, the Exchange client will not be installed.