There is no supported method to reletter the drive that hosts the XP operating system.
This usually happens when we leave the ZIP drive installed. To fix we remove the ZIP drive and start over.
When I received my computer from Dell, my hard drive is designated the F: drive. I dont know why. I need it to be the C: drive. Sometimes downloads go only to the C: drive. For instance online backup for Quicken. How can I rename my hard drive?