Try going
here and downloading a Win98 Boot Disk. Download the red one.
Put a new floppy disk in your A drive then double click the file you downloaded and it will create a Win98 boot disk.
Set your bios to boot from floppy first save and exit the bios.
When the machine boots to this new floppy it will give you the option of booting with CD Rom support, Select this and when it's done booting it will say which drive is your CD Rom probably E:
Type E: then enter type setup then enter again.