There is no big mystery. It is rather striaght forward.

1. Make sure you have a boot disk with CDROM support. The win98 ERD disk is
ok.
Check the disk to see that you can access the CDROM after booting this disk.
2. Make sure you have the win98 product Key
3. Make sure you back up any data you want to save since formatting and
reinstalling will eliminate any information on the drive.
4. It is a good idea to save items like address books, phone numbers, hook
up information for DSL or Cable or phone and the configuration information.

When you have what you need then boot the floppy disk.
At the A: prompt   type
a:> format C:  <enter)    This will start the format application and format
drive C:

After Formatting is complete then at the A:> prompt type
a:> d: (assumes you only have one drive and the CDROM drive was assigned D
drive letter - if another use whatever drive letter was assigned)

At the prompt type CD win98.  Then type SEtup at the next prompt. Setup will
start -follow instructions

For information on installing W98, go to:
http://home.satx.rr.com/badour/html/w98_restore.html