CD-ROM Drive Letter

You don't state your OS, but in win2k it may help you to go into the computer manager in programs > administrative tools. Then to Storage > Disk Management, and you can edit drive letter allocations from there. if you right click on a drive, select Change drive letter and path, and then select the current allocation and edit it you can move drives around. This works for hard drive partitions, CD drives, etc.

NOTE: if e has become d and d into e for example you will have to move say e to Fthen d to e, finally moving f back down to d. with a restart in the middle otherwise the drive letters won't be available to switch to.

You may find some joy in the removeable storage options there also. I haven't had oportunity to play with it.

This is of course assuming you have Win 2K!

Did you recently add a second Hard Disk drive?

With the exception of Windows XP, (and perhaps W2K) Windows assigns drive letters as follows:

Master HDD Primary partition: C:
Slave HDD Primary Partition: D:
Master HDD Logical drives: In order
Slave HDD Logical drives: In order

CD/ZIP/DVD drives are then assigned letters in the order of there connection to the IDE controller.
Primary Master
Primary Slave
Secondary Master
Secondary Slave

If you changed how the drives are cabled, that would also change the assigned drive letters.

If you did not add a drive, or change the cableing, start by removing ALL 3 IDE controllers from Device Manager.
Re-Boot.
Allow Windows to install the drivers.

Other options:
You can manually assign 'free' (unused) drive letters to any removeable media drive.
Move the ZIP drive, and other drives as needed so that you can re-assign the DVD drive as D:

Download and install the latest IDE driver for the chipset on your motherboard.If it is a name brand system, start at the mfgs web site.
Otherwise, use the motherboard identity tools at either www.motherboards.org
or www.wimsbios.com

If you are running W9X, there is a link to a utility that allows you to assign specific letters to hard drives at www.aumha.org

Chas

Are you sure that your cables are correctly attached. I seem to remember that I had a similar problem with a floppy drive and it was incorrectly attached to the cable. If you removed or added any cables during the installation, you might check both ends of the ribbon cable. Hope this helps.