Ok so you are using a different floppy than I thought go to school or some computer and download this and have a blank floppy handy to make your own bootdisk I need you to use this disk to do what I ask.
for get everything if you finally have a floppy and cd working do the following.
type boot from the 98 boot disk and when it loads type "fdisk" then choose option 3 I believe to deleat all your partitions. Reboot if nessesary then choose option 1 if I remember to creat a partition. Reboot if nessesary. Now when the boot disk loads this time just type "format c:/" or "format c:". When you are done formating your partition the hard part begins.
If you made it this far great. Now change to your CD directory. you can do with by typeing
"cd drive letter
ex.) cd E:
Now when you get into the proper directory type "dir" it will give you a list of files you are looking for setup.exe. It may be in a folder called 98_SE if you are using a MSDN CD. If you found setup.exe type "setup.exe" or "cd setup.exe" if you think it is in a folder use the "cd folder_name" command. then type dir again and see if setup.exe is in that folder.
I'm sorry but I can't really explain DOS anybetter and if someone gives you another method just tell them you cannot boot from a CD becuase it was before interupt 19.