There are a huge number of reasons why Windows XP fails on shutdown. Generally it's is caused by a process not terminating as expected during the shutdown procedure.
This link leads to a Microsoft technical bulletin which assists in the diagnoses of shutdown problems on Windows XP and is more indepth than can be provided here.
mobile phones
No, Roblox is not shutting down, and there are no other information to prove that it is. Thanks.
yes they are shutting down nasa
No. Minecraft cannot be shut down. But if you mean if it will stop updating, that will not be any time soon
No, Aeropostale is not shutting down stores.
Yes because people said it's shutting down
They aren't shutting own webkinz.
no you are shutting the coumpter down whats the point?
What do you call when something hangs or sinks down low?
Minimonos shutting because other websites
Specifying the Operating System would help a lot, but I can give you a generic break down of a typical Windows machine which is the safest guess. If it is exiting the operating system, going to a blank screen and not shutting off it could be a faulty Power Supply(PSU). If your operating system is still visible while shutting down and not shutting off, you can have a background program running that is causing a conflict or is malfunctioning. You may want to view your Event Viewer or when shutting down wait for an error message to tell you which program is having an issue when shutting off. This will allow you to disable to application causing the delay.
Have you tried shutting down all programs, then shutting down and re-starting your computer ?