Some older versions of FDISK won't even let you see NTFS partitions.

The newer versions recognise them as "non-DOS" partitions, so that is what you have to look for.
Should be able to delete a NTFS partition with a win98SE boot disk. If you only have win98 first edition, go to
www.bootdisk.com and d/load a win98SE boot disk file. Make the boot disk. Load it up and run FDISk, and kill any non-DOS partitions of the drive.
That should kill it.
More than one way to skin a cat!
Cheers
Mick
Welcome to TechIMO, BTW!