when I press shutdown/Restart, doesn't perform the
funcion, freezes at "windows is shutting down" have to
manually shutdown. Please help

Some of these issues may not be relevant to your Shutdown situation.  Skip
the ones that aren't relevant.

1) Freezes at a blank gray background while shutting down

Try disabling the "Clear virtual memory pagefile" setting via the local
security policy.

2) Hangs at a blinking cursor while shutting down

Is Veritas installed?
http://seer.support.veritas.com/docs/260097.htm

3) Shutdown.exe fails to shutdown server

PsShutdown.exe in the free PsTools suite may work better:
http://www.sysinternals.com/ntw2k/freeware/pstools.shtml

4) Desktop remains up, no shutdown response to CTRL-ALT-DEL or Start >
Shutdown

Possible ACPI issue.  Give this article a full read.  Title is
'Troubleshooting Windows XP Shutdown Issues' but info is relative to Windows
Server 2003 as well.

http://www.theeldergeek.com/shutdown_issues_in_xp.htm

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