*** we assume you have already tried reinstalling the hardware in Control Panel "Add New Hardware" and that it failed.
There are many reasons for this problem. Therefore you will need to try a number of fixes.
Sometimes CDROM burning software such as Nero can cause this. If you
noticed that the drives vanished after installing a CD burner, then uninstall
your CD burning utility and test your CD drives. If they have come back
- reinstall the software and re-test. If still no worky - try the
following solutions in order :
1) Watch the boot process at the beginning - make sure the CDROM drives are recognized (they should be found by BIOS along with your Hard drives and display
briefly on the screen - some PC's don't show them, though)
2) Download the registry fix here cdgone.reg,
run the file, and reboot
3) Place a CD in each CDROM drive - Reboot to DOS with a boot disk an try to access them. If you can't, check the Master/Slave jumper settings on all CDROM drives and all Hard Drives. There should be two ribbon cables - each ribbon cable connects to two drives - one muct be set as Master and the other as Slave.
3) Boot to XP
Right click on My Computer icon
Choose Manage
There you will most likely find that
your CD units share drive letters with
your HD. You can change letters there.
4) Start/Run . . . RegEdit and go to:
HKEY LOCAL MACHINE\SYSTEM\CurrentControlSet\Control\Class\{4D36E965-E325-
11CE-BFC1-08002BE10318}
- you may see what looks like many entries of this key, but read the first 8 digits, they do differ and there is only one of them !!!
Locate the Upperfilters and Lowerfilters values. Right click each and
select Delete.
Reboot
5) Delete the following 4 Registry keys, as per the
instructions above:
HKEY LOCAL MACHINE\SYSTEM\CurrentControlSet\Services\Cdr4 2K
HKEY LOCAL MACHINE\SYSTEM\CurrentControlSet\Services\Cdralw2k
HKEY LOCAL MACHINE\SYSTEM\CurrentControlSet\Services\Cdudf
HKEY LOCAL MACHINE\SYSTEM\CurrentControlSet\Services\UdfReadr