How to Change Hard Disk and CD-ROM Drive Letter in Windows XP?

You can change your hard drive letter or your cd-rom drive letter, the giving steps help you to do this: 


Click the start button then go the Administrative tools option.

In Administrative Tools, go into Computer Management option then click on Disk management under Storage option. Here in lower right corner you will option to change.
Option from the "assign the following drive letter", select the letter you want to assign to the hard drive or the cd-rom drive then click Ok.