click browse, find the file c:\windows\system32\shutdown.exe
replace c:\windows with whereever windows is installed on ur machine
Give it a name, choose perform daily,
choose the time, frequency
put the username of an administrator account and password
Check open advanced properties, click finish
under Run, add these switches:
-s -t 60
so the run box should look something likee:
c:\windows\system32\shutdown.exe -s -t 60
change 60 to any number of seconds you want to, this is how much time u will be given before the machine is killed. to abort a shutdown (once you get the window with the countdown) click start->run type shutdown -a
g'luck!