There is little bit command to shutdown Windows PC like XP remotely from Ubuntu terminal.
For Shutdown windows:
net rpc shutdown -I 10.0.2.60 -U user_id%password
For abort the Shutdown:
net rpc abortshutdown -I 10.0.2.60 -U user_id%password
Here user_id means your windows User ID like Administrator or User and password means the windows User password.