[Rajannl]

My PC is not shutting down with the 'shut down' click. I have to manually switch it off

 

[The_Janitor]

Boot to Safe Mode and see if it will shut down normally from there. If yes, it's an application that is causing the hang.

 

[spunk.funk]

Try these ideas: Advanced troubleshooting for shutdown problems in Windows XP

 

[supportpc]

I found it useful for you - You cannot log off, restart, or shut down your Windows XP-based computer