Cause: This is a known issue in older XP releases, and can be patched by upgrading to Service Pack 1. Also, some software drivers “lock” during the shutdown process, preventing Windows XP from shutting down completely.
Solution: Upgrade your system to at least Service Pack 1. Update the device drivers. If the problem persists, uninstall problematic devices through Device Manager and all their associated software, and restart the computer. Windows XP will auto-detect the hardware and ask you to provide the location for the software drivers. Specify the location of the new drivers and let Windows complete the installation. Some devices may require a firmware update. See the Updating the BIOS section of this guide to understand the general principles on how it is done. Refer to the manufacturer’s Web site for details on the exact steps to be followed.