Are both 98 and 2000 installed on the same partition of
the c: drive or are they on different partitions? You may
not need to fdisk the entire drive. If they are on
different partitions you could just format the partition
that contains Windows 2000. Installing both on the same
partition of the drive is not recommended. Go to the
microsoft.com/support site and search the Knowledge Base
for "dual boot 98 and 2000", read articles 221061 and
289283.