If you want an even more thorough wiping, go for DBAN: It's a program that writes every bit on a hard drive to a 0, which reaches areas that the format command can miss.
http://dban.sourceforge.net/
You can download this and burn to a CD, or a floppy disk on a friend's computer, if nessecary.
However, it's a moot point if you can't boot to a disk--can you describe with more detail how the computer refuses to boot from a CD? Are you just not prompted for a CD?
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Go, Speed Racer, Go!!
"Celerons are genuine Intels, just they are made of celery." - Ebackus, 12/29/05