Win 98 can't access NTFS drives without NTFS drivers being installed. You need to pay for these if you want read/write access, but you can recover files (read-only) with free apps from DOS (if the drive is recognized). You may need to connect the external temporarily as an internal in order to recover the files you want. You can then remove the partitions, create new ones, format FAT32, and access it as an external from 98.
NTFS for Win98http://www.sysinternals.com/Utilities/NtfsDos.html