You will need a boot disk and add format.com to it and also fdisk...You will need to fdisk the drive and change the FAT (File Allocation Table) from FAT 16 to FAT 32 for Win98... we can "talk" you thru doing fdisk..and there are several moves once you start fdisk running, but its not difficult.
Go here to download a bootdisk file.
http://www.bootdisk.com/
In this case, I would choose the first one at the top "DOS - Windows 9X/Me/NT/2K/XP Excellent Bootdisks "..then on the next page, download this one: Windows 98 SE Custom, No Ramdrive. When you get this file downloaded, you will place a formatted blank diskette in your A: drive and run the file..it will automatically extract itself onto the floppy disk..and you will have a bootable diskette with format.com and fdisk.exe already there..plus other good utilities
Now, go here and read about doing an fdisk.
http://www.computerhope.com/fdiskhlp.htm
Once you have read a little and made your boot disk..you will be better able to ask and understand the questions and answers.