WINDOWS XP SHUTDOWN & RESTART TROUBLESHOOTING

Shutdown & Restart problems in Windows XP can be caused by many factors, just like earlier versions of Windows. These included: a damaged exit sound file; incorrectly configured, damaged, or incompatible hardware; conflicting programs, or an incompatible, damaged, or conflicting device driver ,check here for details http://tinyurl.com/2lo659

Pay particular attention to the discussions on Device Manager found here:SHUTDOWN & RESTART TROUBLESHOOTING

"How to start your computer by using the Last Known Good Configuration"

As well as reverting the system to a previous configuration by means
of System Restore: System Restore