stripping linux from a box

[Agner-Nichols]

My childrens' school has a machine with what looks to be a Debian
installation
with boot from the hard drive.  They want to strip Linux from the box and
install the
other OS.  Did the drop partition through fdisk.  But on reboot, instead of
getting
a no operating system found message, LILO kicks in and then dies with a
kernel panic.
I'm presuming that LILO wrote to the master boot record.  So how does one go
about
fully expunging Linux?