Error message: CD ROM must be in drive X (but your CD is in another drive)

Windows 95, Windows 98, and Windows ME users

Open the Device Manager. 
Click the "+" next to "CD-ROM" or "DVD / CD-ROM drives". 
Double-click the drive you wish to change the letter for. 
Click the "Settings" tab. 
Where the computer lists the start and end drive letter enter the start drive letter you wish 
to change the drive to and click ok. 
Restart the computer. 

Windows 2000, Windows XP users

Users who wish to change the CD disc drive letter in Windows 2000 and Windows XP 
must have Administrator rights. 
If you are logged in as a user that does not have these privileges log out and 
log in as a user account that does have these rights. 

Open Control Panel. 
Open Administrator Tools. 
Open Computer Management. 
Open Disk Management. 
Locate the drive that you wish to change the drive letter and right click on that drive 
and select Change Drive Letter and Paths. 

When attempting to change the drive letters on your disc drives you can only change 
the drive to any drive letter after the hard disk drive. 
For example if your hard disk drive is C: you can only change your CD drive to D: through Z:. 
If you have multiple hard disk drives and/or partitions and your last drive letter is F: 
you can only change your CD drive to G: through Z:. 
Finally, computers will never allow a CD-ROM to be setup as A:, B: or C:.