hi;
you're really much better off buying a Lite-on CDRW if possible (or similar, lite-on is generally a good cheap drive) - rather than trying to use MS Backup - you'll regret it.
Also - there's Symantec (Norton) "Ghost" for creating and using backups, but you'll need a CDRW anyway and it costs $ too - there are other software as well (some free) . The thing to have is the CDRW drive and burn CDR backups.
Also trying to use floppies for this is a mess to say the least, though for some small Data or Docs backup, it's ok
TT4U
Notification:
These are just my thoughts....and should be carefully measured against other opinions.
Backup All Important Data/Docs