OK, defragging has corrupted something in windows, but it should
not prevent you from booting from floppy or CD, because these
are controlled by the BIOS.

During boot, there is no operating system running, so no matter
how many critical OS files may be damaged, they can't affect
the ability to boot from floppy or CD.

Something else must be affecting the floppy and cd drives.
The floppy, I would first verify that the disk you try to boot from
is not bad. The CD, likewise, first check the integrity of the disk,
then go back and check all the usual suspects, BIOS settings, cables,
etc.

You should be able to get it to boot from the CD, no matter what's
happened to windows.