Windows XP wont shut down

[A_DOG73]

I got a friends computer here. It is a dell dimension 3000 running xp. When I press start, shutdown, the mouse arrow gets a little clock next to it for like 1/2 a sec like it wants to shutdown and then dissappears and the computer doesn't shut down. Also the same with restart. What could cause this?

 

[Peddant]

This is the best guide to XP shutdown issues on the net.- http://aumha.org/win5/a/shtdwnxp.php