FC4+KDE.I have one good cdrw with some data.My pc is worked well so far.Suddenly the linux could not able to find the cdrw in the drive.The drive is working well for all cdrw except for this one.So the problem obvious, and with my cdrom.How can be?the same cdrw can be identified by windows.so look at the result.

[root@localhost ~]# mount /dev/hdc /mnt/cdrom/
mount: No medium found
[root@localhost ~]#

[root@localhost ~]# dmesg | tail
lp0: using parport0 (polling).
lp0: console ready
eth0: no IPv6 routers present
[drm] Initialized drm 1.0.0 20040925
PCI: Found IRQ 10 for device 0000:00:02.0
PCI: Sharing IRQ 10 with 0000:00:1d.0
[drm] Initialized i915 1.1.0 20040405 on minor 0:
mtrr: base(0xe0020000) is not aligned on a size(0x300000) boundary
NET: Registered protocol family 4
NET: Registered protocol family 5

[root@localhost ~]# dmesg | grep ATAPI
hdc: ASUS CRW-4832AS, ATAPI CD/DVD-ROM drive
hdc: ATAPI 48X CD-ROM CD-R/RW drive, 2048kB Cache, UDMA(33)
[root@localhost ~]#


[root@localhost ~]# dd if=/dev/hdc of=/root/cdrom.iso skip=10M bs=1
dd: opening `/dev/hdc': No medium found
[root@localhost ~]#


So can somebody help me out of this problem.

Either there is nothing in the drive, or it is too dirty/scratched to read.
If windows can still read the disk I suggest you clone it.