I have a computer that will not shutdown. Windows XP acts like it will shutdown, the screen turns blue, the mouse and keybaord shutoff, but the mouse pointer is still on the screen and it locks. The mouse is optical; so I can see it shutoff. The other identical computers shutoff at the same time the mouse turns off.
cookies, spyware, and adware can cause this problem I have had it before. I cleaned the systme using a program and it worked fine afterwards. It can also be your network connection if you are connected to the internet. I use an HPNA adapter and it sometimes causes it to hang up upon shutdown. I have yet to find a fix for this.
I would say that there is a low possibility for spyware. This was a new install. I even have Deep Freeze and Norton Installed on it. It has only been online a few times. I'm not saying that isn't the problem though. I will look into it.