Dual Booting

Currently I had a harddisk with 20GB.

NTFS c:\ – winnt wks 4.0 16GB
NTFS d:\ – file 4GB

I want to install Winnt Server 4.0 in c:\. I try using Parition Magic but it give me error that Windows cannot install on disk more than 4GB.
Note:Please do not use ask me to FDisk and re-install all my applications.