well, it depends on what kind of softwear you had to burn your cd.
Cdrw dvdrw
i have nooo clue there is something called try using google wattt:P
CDR CDRW DVDR DVDRW Blueray
its either a re-writable disk or its not!
Yes.
CD-RW
A floppy disk DRIVE can read, erase and save information on a floppy disk. The disk can't do it by himself.
Yes, of course!
go to disk utility and you have the option to erase there
Formatting your hard disk for the PS3 will erase everything on it. If you are adding a hard disk to your PS3 it will prepare the drive for the system.
Yes - that's basically what a hard disk is for. Perhaps I'm missing your question - can you rephrase it?
Go onto "My Computer" right click on the disk, and then select "Format" it will not entirely erase all the data on the CD, but it will erase majority of it.