Are you reformatting your Win 98 computer?
Is it 98 or 98SE?
Bootdisk.com seems to have different downloads for 98 and 98SE, though I'm not sure it matters for your purposes. http://www.bootdisk.com/bootdisk.htm
After you download one and put it on a floppy, make sure it works before formatting. You should be able to access your CD drive using the bootdisk.
To format, boot of the floppy and type
at the prompt. It will probably ask you if you really want to do this, so type Y and Enter for yes. To access the CD drive, type the drive letter followed by a colon and enter it. If the boot disk has created a Ramdrive, your CD drive letter will probably be one letter higher than what it usually is (unless the computer is an HP or something and usually has the drive letter as M: ). If your drive letter is usually D:, it may end up being E: when you boot off the boot disk.
To install Windows, access the CD drive, type
and enter it. It should prompt you.
I assume you've saved everything you need that is on your C: drive.