I have a windows xp pro machine that is having a problem shutting down and rebooting. Whenever I choose shutdown or reboot, it seems like the machine gets to a point and then stops the shutdown process. There are a bunch of icons in my system tray, but when I move the mouse pointer over them, all of them disappear except the network icon. I have to press and hold the power button to make the machine shutdown. Then when I bring it back up I have to restore my active desktop. What could be causing my machine to not shutdown and restart????????