Are you talking about dual-booting? If so, no. But if you're talking about upgrading from XP to Server 2003, then it's a different story... it won't upgrade. You'll have to back up your data and reload.
You are about to answer a thread that has been inactive for more than 6 months. If you still wish to proceed, please ensure that your posting is original and does not duplicate or overlap any prior responses to this thread.