Changeing letter of hard drive

My old hard drive went bad. I replaced it with a new one. The same brand and size. When I reinstalled Windows XP Home on my new hard drive. The system assigned the letter “E” to the hard drive and “C” to the Zip drive. I changed the Zip drive to “Z”. However when I try to change the hard drive to “C” I get the message “Windows cannot modify the drive letter of your system volume or boot volume”. I have one hard drive in my system.
Can it be changed without reinstalling the OS?