could not find cdrom after mount iso file

[owen nirvana <freeespeech@gmail.com>]

I try to do so at  some machines at my hands. Even if I re-install from zero, computer could not find cdrom(/dev/cdrom, /dev/hda/ ..., nothing), and I used -d when umounting iso.

I don't know it is a problem of gnome or debian. 

thanks for help!

gtalk:freeespeech@gmail.com